I need to have some jeans and trousers altered but all the local tailors are beyond useless and have already ruined two pairs of jeans. I need a tailor that I can post the jeans to, with a sample pair to show him how I want them.
Why not? The tailor I used to use in London (shut down now ) would take a pair of jeans that fitted me perfectly and use that to show him how I wanted the new pair. I would give him them and say "Make them exactly like these, please."
My wife offers such a service, all profits donated to the Children's Chronic Arthritis Association. PM me and I'll pass her email on to you. Obviously if done by post all measurements are your responsibility!