Plane tickets – use your favourite flight search engine. If you don't have a favourite, try kiwi.com.
Car rental – use AVIS. The rental desk is right in the arrivals hall. Remember, in the UK they drive on the left. If you're not confident enough about it, you'd better get full insurance – you'll be able to get it when you rent the car.
Tickets – if you're visiting in the summer season, you'd better get tickets in advance, at least for The Beatles Story, and for the British Music Experience.
Check opening times – be sure to check the opening times at Plas Cadnant Hidden Gardens. Adjust your programme accordingly.
Calling and data – remember that the UK is not part of the EU, so check with your provider for call and data prices. Wi-fi is common in hotels and restaurants and is free.
When to go – pretty much any time except winter months. In the summer months there are a lot of people here, of course. So, it's best to come here in spring or autumn.
TIP – if you're a really passionate fan of The Beatles and really want to see everything then consider taking one of the "Beatles tours" in Liverpool in addition to the individual programme. There is a lot to choose from on the internet. Or you can try Mop Top Tours, which does half and full day tours and has excellent references.

