England and beyond advice

My husband and I are making a quick trip to London for a wedding. We plan to take about 8 to 10 days there. We were in London less than 6 months ago so we have done and seen a lot at that previous trip. Since we need to be in London for a Friday wedding during the summer any advice on where else we can go and come back to London ideally day trips like first flight/ train out and last in or an overnight somewhere? We are not museum people so skipping those recommendations please.