Empty Nest - cheap days out?

[Menonut]

Just that really. Son is now in his 20s so just me and DH. He’s a teacher so has 6 weeks off. I’ve got annual leave taking me up to when he starts school again.
We’ve got National Trust Membership but have visited all the local ones.
We can’t afford to drop £50-100 on tickets and food every time we have a day out and I’m fed up of the never ending “what do you want to do?” “I don’t mind - what do you want to do?”
We’re on the south coast between Bournemouth and Brighton, fairly close to Portsmouth.

Swim in the sea or lido. Take your own picnic.

I think you can get a 3 month trial of the National Art pass for free entry to galleries and some other attractions.

Train to London for the parks and free museums. Get a cheap lunch and take some food/drink with you.

I would say see if you can get a cheap spa day deal or even day trip abroad, but that's likely to be above your budget.

Switch your bank account for free money. Also if you haven't already, review all your expenses to see what other savings you can make.