Never found anytthing that worked. Wish there was.

I think that you will find that the wasps are only taking a tiny amount of wood from your fence, Val. I would just let them be.

Well it is vanishing rapidly ! I will try and get a photo later .... thanks ... Val

Hate the noise of them scraping away at the swing seat in the evening. Really sets my teeth on edge.

They are using the wood to build their nest!

.... and we have found their nest !!!! in the little corner of the garden which is where we usually chuck odd pieces of grass,turf etc and keep it in a mound - not the compost bin though .... we found that if we overturn turfs 'grass to grass' they eventually turn into nice soil !!
My husband was just strimming some of the long grasses which had grown there and three flew out of a hole in the turfs and stung him !!
Not sure what to do now as I absolutely hate wasps and won't go near them, plus we have a small grandson who comes on a Sunday and is into gardening !!
Is there anyway we can get rid of them or will we have to call out the council ?? .... Val

If you really feel you have to, Ismeval, your garden center has products to kill the wasps in their nest. Just make sure that you follow the instructions.

Thanks - will check it out - I really don't want wasps round here and risk them stinging my little grandson .... Val

We have a pest control man coming over this evening to sort it out thank goodness ... Val