Things to do/visit near Harry Potter studios (Watford)?

[shaggedthruahedgebackwards]

We will be venturing 'down south' soon for a trip to HP studios (both DC are big fans)

I assume the studio tour will only take half a day so just wondering if there are any other places or attractions anyone can recommend that are nearby?

Prefer not to go further South or into Central London as driving home later the same day

A couple of ideas.. Roald Dahl museum in Great Missenden and National History Museum in Tring

Half a day for HP world?
Both times we have visited we spent around 4 hours in there - now they have a 'forbidden forest' section I expect it will be a full day trip .

Thanks both

I'm just guessing Soon, I've never been but our tickets are for 9:30am so was assuming we might be done by about 1pm?

My niece went a month or two back and was there from 9.00 ticket until gone 3.
Roald Dahl museum is lovely but only if your DC love his books.

Apparently there's a fire brigade museum in Watford which gets good reviews!

St Albans is about 20 mins away...roman remains, museum, cathedral, market. You can follow a treasure trail which is kind of fun treasure maps.co.uk (6.99) The trail takes 2 hours. There's a trampoline park (gravity force) and a museum if the weather lets you down.