Diazepam is slowly being phased out in the UK. You can switch to another surgery but I fear in time this story will be repeated.

You do have a right to be given an alternative med for your anxiety. I would say the nearest and best alternative is pregabalin, which some GPs are also reluctant to prescribe due to cost. However, in your case, this might be overlooked.

You should also ideally be given a withdrawal plan but, again, this is at discretion of GP. Some might consider it unnecessary. But I would raise this issue all the same.

Lastly, the herbal route discussed above is also an option. Magnesium is a good muscle relaxant but has a habit of causing diarrhoea, so dose must be titrated accordingly.