M&S has launched their Spirit of Summer range and is currently offering 4 small deli picnic items for £10 with a free cool bag, cutlery holder or bottle of wine. Unsure which bottles of wine are available under the offer, but the cool bag (pictured) is a good size and great quality with a zip on the top, and scanned through at £8 before the discount came off.
Picnic items cost around £3 each outside of the offer, and there is a great range available, which includes pulled pork wraps, shredded ham, chargrilled chicken, sliced belly pork, serrano and manchego rolls, marinated feta, olives, sun-dried tomatoes, lamb koftas, sweetcorn empanadas from what I remember. Not huge portions of the meats etc., but olives and feta seem to be the regular full size ones that M&S usually stock.
EDIT: Deal is £9 for Sparks card members until Saturday 14th May (you can pick one up in store if you don't already have one, don't need to send away for it). Thanks @scoffer1 and @baggerofbargains.