London (Floor 4, Bankside 3, 90-100 Southwark Street, SE1)
Best for: Large retailers running a loyalty programme that want CRM and loyalty work that award judges have assessed in retail and data categories
A global precision marketing agency, by its own description, with a London office on Southwark Street. At the 2024 DMA Awards its work took gold in the Retail and E-commerce category for IKEA loyalty, and gold in Data and Insight for Ralph Lauren loyalty. Its awarded retail work is loyalty programme work, so it is most relevant to retailers that run or plan a loyalty scheme.
- At the 2024 DMA Awards, RAPP won gold in the Retail and E-commerce category with "Nudging up Loyalty for IKEA".[6]
- Its "TAIloring loyalty for Ralph Lauren" work won gold in the Data and Insight category and bronze in the Email category at the 2024 DMA Awards.[6]
- RAPP describes itself as a global precision marketing agency, and its locations page lists a London office at Floor 4, Bankside 3, 90-100 Southwark Street, SE1 0SW (self-reported).[7][19]
London, with teams in Dubai and Auckland
Best for: Retailers that want email and SMS journeys driven by purchase and stock signals, and judged on incremental value, category contribution and repeat purchase rather than send volume
A growth marketing agency founded in 2022 with a team in London. Its retail retention and lifecycle service audits the moments when customers activate, lapse or buy again, designs email, SMS and in-product journeys using purchase and stock signals, and measures incremental value and fatigue by cohort. It says lifecycle work connects with acquisition, CRM, data and customer insight.
- MxD Digital was founded in 2022, has teams in London, Dubai and Auckland, and says it has helped 30+ businesses across seven industries.[1][2]
- Its retail retention page says the audit takes in product availability, category margin, store and ecommerce behaviour and the promotion calendar, and that journeys use purchase and stock signals for replenishment and cross-category messages.[3]
- It says it measures incremental value and fatigue by cohort, then adjusts timing, content and suppression rules, and that in retail it also checks new customers, category contribution, returns and repeat purchase.[3]
- Its retail page says it reports against contribution margin after returns and uses incrementality tests rather than platform-reported ROAS.[4]
Beenham, Berkshire, according to Clutch; its website publishes no street address
Best for: Online retailers on Klaviyo that want a specialist email, SMS and retention team to run the account end to end
An ecommerce retention agency offering CRM audits and roadmaps, retention strategy, creative, automations and flows, and SMS and WhatsApp management, with email as its core. Klaviyo named it one of three joint EMEA Agency Partners of the Year in 2025, and its Klaviyo directory listing names retail clients across apparel, beauty, home and food and drink.
- Klaviyo named Underground Ecom one of three joint Agency Partners of the Year for EMEA at its inaugural K:Partners Awards in 2025. This is a platform vendor's award, not an independent one.[8]
- Klaviyo's partner directory lists it at Master: Elite tier, serving retail in apparel and beauty, food and beverage, home and electronics, and outdoor, and names clients including AG1, Huda Beauty, Oh Polly, Chilly's and Wild.[9]
- Clutch lists its headquarters in Beenham, England, a founding year of 2018 and a 100% email marketing focus for ecommerce clients, though it shows no verified reviews.[10]
- Its website lists CRM audits and roadmaps, CRM and retention strategy, automations and flows, and SMS and WhatsApp management, and says it has a team of 120+ (self-reported).[11]
London, according to Klaviyo's partner directory; its website publishes no street address
Best for: Direct-to-consumer and Shopify retailers that want a smaller specialist team for email and SMS strategy, design, segmentation and copy
A London email and SMS retention agency that describes itself as a full-stack retention marketing team for DTC brands. It covers strategy, optimisation, design, automation, segmentation and copywriting on Klaviyo and Shopify, and shows testimonials from brands including SURREAL, HUX and PÄRLA.
- Klaviyo's partner directory lists ElliotDigital as a Platinum Master partner based in London, with Shopify and Shopify Plus expertise, and includes a testimonial from SURREAL's co-founder.[12]
- Its website describes it as a full-stack retention marketing team for DTC brands, offering strategy, optimisation, design, automation, segmentation and copywriting for email and SMS (self-reported).[13]
Poole, Dorset; its website publishes no street address
Best for: Ecommerce retailers outside London that want email, SMS, push and loyalty work focused on deliverability and lifecycle segmentation
An email and retention marketing agency founded and headquartered in Poole, which says it combines email, SMS, push notifications and loyalty programmes, along with deliverability work and ESP set-up and migration. Its evidence is thinner than the others here: a Klaviyo Platinum status and no named retail clients on its website.
- Dorset Chamber reported in April 2026 that Enviary, founded and headquartered in Poole, had reached Klaviyo Platinum Partner status and works mainly with ecommerce businesses on lifecycle strategy, segmentation and optimisation across email and SMS. The item reads like a company announcement.[14]
- Its website lists retention marketing across email, SMS, push and loyalty, customer journey design, deliverability, and ESP set-up and migration, with case studies labelled by sector rather than by client name (self-reported).[15]
