Bath/Stonehenge from London

Hello all, any advice/recommendations would be much appreciated! My mum is visiting from abroad in a couple of weeks and she really wants to do a day trip from London.

She is set on going to Bath but we were a bit confused about Stonehenge, is it worth a visit? We were looking at tours originally which would be around £145 per person including transport and entry to stonehenge and the roman baths, but I have also looked at trains and booking stuff ourselves as a cheaper option. Just fyi both stonehenge and roman bath tickets would come up around £68 per attraction (for three people) so just under £140 for both attractions for 3 people. We are looking to go on the 9th of Feb!

If anyone has any ideas or knows any affordable tour companies please comment below, and if stonehenge is worth a visit or just a day in bath is better?

Thanks in advance <3

Edit - seen some comments around about Windsor + Bath in one day, is that any good/viable?