Harry Potter Studio Tour (Watford) + Hotel with free parking from £38pp based on a family 4 (2A & 2C) staying at the Mercure London Watford Hotel which is approx 2.5 miles from Harry Potter Studios itself. -This was on 29th April (prices may differ slightly)

Also if you sign up via Earnaway you can get a bonus £12 cashback on a £25+ booking and laterooms has a decent cashback rate so i got another £5.80 cashback on top = £17.80 back in my pocket.

Hotel has free parking outside with plenty of spaces, McDs is literally next door and Watford town centre is 2 miles away with plenty of parking and a huge shopping centre and lots of resturants (stuck a load of info in 1st post)