Another vote for Dr Eldimarys Curry at SW11 Medical on Lavender Hill. She is extremely knowledgeable and experienced and can advise on the best treatment for you. It's also relatively reasonably priced. I am now 49... I had her do my Botox regularly, I had filler in my lips, cheeks and nasolabial folds, and also had "threads" (non surgical lift), and recently I had a filler on my nose - that's a non surgical nose job, and I couldn't believe how well that worked - I went from having an (increasingly) crooked nose to a nearly straight one! I don't look "done" but people can't believe my age
For frown lines, it usually is Botox, but sometimes if your lines are deep, a bit of filler can go a long way.
What I like about Dr Eldimarys is that she only does a little initially, then saves your Botox (or filler) and you come for a check-up 2 weeks later so she can top up based on how it worked for your face and / or how you feel about it.
Best of luck and happy to provide more advice if you PM me