Plants on ebay eh? What a fascinating subject!
First of all Seanie you ask about plants for a shrimp tank. All plants entering the UK are treated with pesticides to kill a whole range of nasties that would otherwise enter the UK. These are harmfull to shrimp and ornamental snails for that matter. If you'd have read the ME pages for JJC Aquatics or Last Trading Post you would have seen this detailed and you wouldn't have needed to email them. ALL plants bought from any source should be thoroughly rinsed to remove all chemical traces before adding them into your tank. Buying an assorted pack wasn't the best decision for shrimp IMHO.
Specimen plants, mosses, Riccia etc come from the same suppliers in the far east as 95% + that LFS use. You pay a massive premium for plants grown in europe. Tropica are often touted as the best, but many plants from "ebay sellers" are as good a quality at a fraction of the price. I've proven this on many occasions. Also, the specialist ebay plant sellers import directly and don't buy from a UK wharehouse were they may be sat around for a week or so before being sold to an LFS which might also have them in stock deteriorating for a few days.
The 25 plant assortments range in price from £4 - £5. If you read the details carefully most ebay sellers detail exactly what species and type (Cuttings included) of plants are supplied. Realistically they're tank fillers and appeal to the masses. Not serious aquarists who are interested in creating a perfect biotope etc.
For the record, the species offered in these packs cost between 2 and 10 pence per plant from far eastern suppliers. However, once you add freight charges, VAT, ebay listing fees, ebay final valuation fees, paypal commisions, Postage and packaging costs, allow for some stock (right off) and a whole host of incidental costs you make around £1 per pack. Oh, and that doesn't include your time. I think you have unrealistic expectations from assorted packs and would be best purchasing individual specimen plants at realistic prices.
Many of the assorted packs on ebay still offer far better value for money than LFS but be realistic about what you expect for the price of a bag of fish and chips!