ta guys. just had a chat with my dad about it, he's got a torque wrench so can make sure we don't over tighten but as the first decent trip after repairs will be all the way down to Cornwall (with an overnight stop) we're a bit nervous about why/how it's got loose with the split pin still there. we're gonna try to have a better look tomorrow, if all looks ok then we'll tighten the hub/castle nut and be done but i can see us giving a garage a call... protective dad and all that
Thanks for the numbers and advise