It's 3 buses and 165mins to get to Gatwick from mine, or a 50 quid uber in one direction only.
Looks like it's about £82 to use the Gatwick Long Stay for 8 days which isn't horrendous considering I'd have to do Gatwick - Clapham - Surbiton to get home
Too early for Thameslink? Doesn't that run all night?