I’m also from the UK, try and be persistent with your GP, I’m terrible at doing this but people that manipulate the system get seen straight away.
Explain it’s causing you great stress, anxiety, and depression and If you can create an emotional attachment like your wife is going to leave you because of it and you’ve just had a warning from work because of your lack of performance since the prospect of divorce they’ll take it much more seriously, unfortunately!
I recently had a dead dick for 2 weeks and was incredibly worried about it, I rubbed lots of castor oil in and took lots of ibuprofen and my erections have got better..
I hope you get well soon.