Lymphedema since Bladder cancer

Hi, I'm hoping others on here that may of had lymph nodes removed/damaged in their groin due to Bladder cancer surgery will be able to give me advice. I had my R.C in July 2012 so a long 12 yrs ago. A few months after I had slight swelling in my left thigh & groin and eventually it vanished only to swell slightly a few times over the years, that is until last summer when My left leg swelled up quite a bit, I saw my GP who didn't seem bothered and didn't refer me to anyone. This summer my left leg is awful I feel deformed and can only wear long loose trousers, my feet get so swollen I can't even put sandals on or shoes, even socks dig into my feet and hurt. The right leg is slightly swollen but nothing like the left. I've shown my G.P and an out of hrs emergency clinician but still no help, the GP even suggested it wasn't Lymphedema but she didn't even look properly or feel the top of the leg where the skin is so tight or look at the dimpled bits. I need treatment but don't know what to ask to be referred to, which clinic/speciality do I need to be seen by ? I'm in the UK but assume it's the same here as in the USA. Any information or advice appreciated. Thank you 😊