Hi Issac!
Welcome to planDisney.
It's always a pleasure to assist my fellow guests from the UK. Thank you for asking this question!
The good news is that our
UK Magic Tickets (7 or 14 days) do not require
park reservations. This rule was changed in January this year. If you chose a specific date when your usage window starts then you do not need to make park reservations, as date-based tickets are excluded from this requirement.
You will have 18 days in which to use your 14-day tickets, from the start date chosen (which could be the date of check-in to your hotel).
Remember that you have
water park admission (Disney's Typhoon Lagoon or Disney's Blizzard Beach, whichever is open) and miniature golf included with these tickets, and entry to those activities does not impact your 14-days of theme park admission. You have 14 days of access to everything. One day of water park fun does not subtract one of your 14 days at the theme parks. I hope that makes sense!
Please come back and visit us if you have any further questions, and you can
send me a direct question if you wish. We will be happy to help you plan your magical holiday to Walt Disney World!
Sue