I'd put £2,000 away for next summer (me and a friend plan to drive through 6 countries in 2 weeks (Europe) and £1,000 for this summer (Magaluff!). That sounds like all of it with the current exchange rate 8(
I'd redo the backgarden, add a pool with an electric fence and charge a fee of $500 per summer, per family since we would be the only ones with a pool in the neighborhood. Then i'd make back $5000+ for other fun expenses.