this sometimes happens but they do taste like ordinary tomatoes and some yellow ones are very sweet.
is it the colour that puts you off? one of my girls just wont try them even though the rest of us tell her they taste the same. ;o)
you should write to B&Q and say they were miss labelled taking a photo of the seed packet and plants if you can. You may get some free seeds for next year.

thanks for comment I'm not put of by the colour its just that I have 6 yellow plum tomato plants instead of gardeners delight which I skin and cook for sauces

ah so the colour may matter for your sauces. still use your toms and if you want to make them look red add a bit of red food colouring. it wont affect the taste.

This is precisely what has happened to me. Verve Gardeners Delight (red) has become a fairly tasteless yellow plum variety. Too much pulp to be really a salad tomato and too yellow for pasta or meatballs. All the effort and nurturing totally wasted. Next year - it is plants from a reputable nursery

I too bought a packet of Verve Gardeners delight seeds and grew 50 plants. All were yellow plum tomatoes. This seems to be a widespread problem for the past 2 seasons. see thread on Gardeners World Forum http://www.gardenersworld.com/forum/fruit-and-veg/yellow-gardeners-delight/986187.html
Also there are seven reviews on B&Q's website citing the same problem

thanks all I will also be buying seeds from a reputable company

I notice B&Q have revamped the listing of all their tomato seeds. They now add the word "Mix" to the end of all the variety names hence one now buys Gardeners Delight Mix, Is this a very sly way of covering themselves for whatever rubbish grows from the packet. Also, it has enabled them to remove the large number of adverse reviews about the tomatoes by selling a "New Variety" and not having the old one for sale anymore. This is a devious underhand practice to catch the unwary.

thanks snowman learnt my lesson will only getting seeds from reputable supplier

I bought what was sposed to be gardeners delight fro a seller on ebay. when they grew I thought they are not gardeners delight, they were like triffids, so big and strong. Then the fruits started to lengthen into plums, not favoured by me, then they turned yellow; again not favoured by me, but when I tried one they were delicious, juicy and sweet. Masses of fruits too. So I saved the seed and three years later sowed 18 seeds and they all came up by one. And they are just as nice though they were planted very late.
This year I had trouble with all my plants except these, they developed twisted mishappend leaves and nothing happened till after new growth appeared and that was normal, I searched the et for answers and foud that nay had same problem, and decided it was down to manure they added to the soil, which had weedkiller in. Didn;t affect the horse but went through to the manure and subsequently my plants. Can't show a photo on this thread, sorry