Store-brand fat-tire e-bike wanted for retail chain — 250 units/year

We're a cycling retail chain looking to add a store-brand electric bike to our range, positioned alongside the third-party e-bike brands we already sell — something we can put our own name and colours on rather than reselling an existing brand as-is. Specification: 250W rear hub motor, 48V removable battery, hydraulic disc brakes, front and rear suspension, 7-speed, steel frame, 20" fat tires. We'd want the frame available in one or two colour options with our logo on the down tube, and neutral otherwise — we're not looking to redesign the platform, just brand it. Volume: approximately 250 units per year to start, released in two or three batches so we can gauge how the store-brand model performs against the third-party lines before committing further. Requirements: CE conformity and EN 15194 documentation are required, and we need confirmation of minimum order quantity per colourway since we may want to test two colours in the first release. Packaging: single-unit carton with our branding on the outer box if that's a low-cost option, otherwise a neutral carton is fine for this volume. Delivery: DAP our Porto warehouse. In your proposal, please include: pricing per unit at this volume, cost and minimum order for logo/colour customisation, lead time for the first branded run versus a standard-spec run, and whether artwork proofs are provided before production starts.