Do any of you use a harness and if so which is the best one on a very strong dog.

The best I've used is the xtra dog harness with a front clip :)

Thanks for that will have a look at the website.

Agree with above, last week I gave one of these harnesses to my sister for her Vallhund boy as he was really pulling and misbehaving, culminating in him knocking my niece flying, now have had back reports that he walks to heel beautifully.

I've got an xtra dog one too. I noticed a real diffrence if I switched between the frount ring and the back ring, make sure you check the length of it if you get one, I got mine last year at crufts last year and I checked it fitted around her but I didn't check it's length and it turned out its a bit too long on the chest to use the frount ring if safely as she can pull back and get her leg out, but if I had checked and got the next size down It would be perfect.

I'd recommend it