when did you last feed them? if yesterday then flush the soil/compost with plenty of water to wash the excess away. if more than a few days ago then keep them well watered and don't add any more feed for at least 6 weeks.

Did you check the use by date?

I agree with SBG. Just flush the area with loads of water & just give it time to recover. I can tell you, the best fertilizer I ever used for my tomatoes is Fish Emulsion. I dilute only a couple cap fulls to a 5 gallon bucket of water. It's super concentrate. My tomatoes plants love it. They are all loaded with perfectly forming fruit. No blight or blossom end rot & vigorous growth.

Flush with loads of water with a drip of washing up liquid

It was over a week ago in fact its only that they have started to look unwell and one clematis that is in the ground has died I realise my mistake. Can't believe I made this mistake. Thanks for your reply's

Yep, I had to learn to read the label first the hard way, myself. Like they say ample watering is the only way to remove the excess. If you follow Darren's suggestion, it will help, but be really stingy with the soap: it's too easy to use too much.

a week on is a bit late but plenty of water to flush the surrounding soil. careful with the detergent as it will irritate/harm many of the soil fauna.