Birthday day/evening out ideas

[chocolatemonster]

DPs birthday next weekend. We have an extended 3 day weekend. Don't want to go overnight anywhere but looking for ideas of something different to do in the day with a meal maybe afterwards.
Have arranged one day - foodie walking tour so looking to fill the other 2 days.
We are on the South Coast so can reach Brighton and London easily.
He likes activities and is quite sporty so looking for something we can both do. Or any day out that's recommended plus a restaurant that's not a chain. Favourites include Thai, French and Greek

Cycling?

Any venues you recommend?

Walking over the O2 in London. Dinner at Hakasan, I think they have two restaurants in London.

Does sporty include running? Start Saturday with a Parkrun - one of the south London ones. Dinner at Chez Bruce by Wandsworth Common. Spend the rest of the day at somewhere like Dulwich Picture Gallery? Or seeing if you can book a drop in session for kayaking or rowing on the Thames

He might be able to run but think I would keel over

Like the restaurant suggestions and the O2/rowing ideas. Will check those out - thank you

Into The Trees festival is next weekend
You could go to Worthing for one of the evenings. There's a good Greek restaurant called The Fat Greek Taverna and light festival on the beach in the evenings www.worthinglightfestival.co.uk
The Anchor Inn is gorgeous and they have boats you can hire to row along the Ouse. Lovely if the weather is nice. www.anchorinnandboating.co.uk

Tough Mudder or similar? I took up canoeing this summer and loved it - is there anywhere you could do that? Quirky pub with craft beers.