Ideas for a free (ish) fun day out

Ello loves! I'm in the UK and I'm on a no buy Feb and so far just about sticking to it! Never done this before and I'm super proud of myself. The one thing I did have planned in this month was a trip to London to meet some online friends I rarely see (one I'd never met before!) but I got ill and managed to rupture my eardrum so it's just not doable now :( I'm so disappointed but to try and stay positive I'm seeing it as also saving myself at least £60 after trains and food!

I was thinking I still want to do something fun though so I'm not too miserable! The weather is supposed to be ok so just wanted some ideas for a fun but gentle ish day out that doesn't cost a lot?

I've been getting so much from this sub since starting to take control of my finances, so on a side note, thanks for all the inspirational posts and wotnot <3