Thanks Shona - good advice.
Don't worry -most people have no idea about Welshies! They are really wonderful little characters but can be truly stubborn little terriers
So far in his other training he has done anything for food but with this "rabbit red mist" as my husband and i now call it he isn't even interested in a food reward.
I have invested in a plain harness so he doesn't hurt his throat and will try taking a squeaky toy instead of food treats incase that works better.

Thanks for all your help btw