The most expensive point to discover that your retail-ready packaging design doesn't meet a retailer's specification is after the print plates have been made. I've watched that happen. The buyer emails back with a six-page requirements document that nobody had asked for before commissioning the artwork, and the brand is looking at four to six weeks of rework plus the cost of scrapped plates.
Getting to that point isn't bad luck. It's a process failure that's entirely preventable.
What retailers are actually testing your packaging against
Most major UK grocery retailers assess shelf-ready packaging against a framework they sometimes call the "five easies." The specifics vary between retailers, but the underlying logic is consistent.
Warehouse staff need to identify the case in a full pallet pick environment without opening it, so all four sides and the top need clear product identification. The opening mechanism needs to work cleanly in under five seconds without tools, because staff filling shelves are handling hundreds of cases per shift. The opened tray needs to fit standard shelf bays without overhang. Products need to be visible and accessible to shoppers without the tray blocking adjacent lines. And the empty tray needs to be collapsible and single-material for the retailer's recycling stream.
Fail any of these and the design goes back for revision, or gets rejected at trial store level, which is considerably more disruptive.
The opening mechanism problem that derails more designs than any other
Every major grocery retailer specifies their preferred opening mechanism in a format document, and they differ meaningfully. Tesco, Sainsbury's, Ocado, ASDA and the hard discounters all have their own requirements for perforation shape, tear strip depth, whether a front lip should remain, and the minimum product visibility percentage once opened.
This matters because designing to one retailer's specification may actively fail another's. A straight tear-off top that Aldi prefers leaves no front lip, which Tesco often requires as a price-ticketing area. If you're targeting multiple retailers simultaneously, you need to establish early whether a single design can meet all of them, or whether you're looking at retailer-specific variants.
Trying to design a compromise unit that almost meets everyone's spec is usually worse than accepting the variants upfront. Almost-compliant packaging gets rejected at trade review.
MOQs and print economics for RRP
Printed retail-ready packaging almost always requires flexographic print or litho-lamination. Both involve plate costs (typically £200-400 per colour) and setup runs that make short runs uneconomical. For most printed shipper trays, the minimum viable run is 2,000-3,000 units. Below that, the economics don't work for the supplier or for you.
If your volumes are below that threshold, a plain corrugated tray with a branded paper insert tucked under the product achieves a similar shelf-facing effect at substantially lower cost. It won't pass a formal RRP assessment, but for smaller independent retailers it can achieve much of the same commercial benefit (product visibility, easy shelf-filling, branded secondary packaging) without the MOQ commitment.
How to protect yourself before tooling is committed
Get written confirmation from the buyer or the retailer's packaging technologist that your design meets their current specification before any plates or tooling are ordered. Requirements do change, and what a retailer accepted two years ago may no longer pass their current standards.
Ask the buyer for the retailer's RRP specification document directly. These aren't always publicly available, but they should be able to supply them. If a buyer can't or won't provide the spec document when you ask, treat that as information about how the account will operate more broadly.