TITG is probably one of the best bike events in UK and there is every type of bike under the sun there. Well worth going to and great to also fit in the best biking roads in UK while up here ;) As has been said it's best to book accommodation asap but well worth the trip.
I'm there working every year doing my bike tours thing for orange and black/HC travel as well as my own European Twisties tours :)
If your interested there's a national Harley group called 'Sportster Sickness UK' which as grown into a large owners group over the years. Totally separate and independent from Hog.
Each year they do a national event called 'The Big One' it was unfortunately cancelled last year, because of the pandemic. But this year it's back on (fingers crossed) at Donnington Park race circuit. Here's a YT video from a past Big One.
https://youtu.be/oq34SeDWUBs
It's mainly Harley's and the Sportster model but all and everybody are welcomed no matter who you are and what you ride. All members come from allover the UK, have different bikes and are from different cultural backgrounds.
If you are interested join on facebook. Just search 'Sportster Sickness' If you don't do FB and your still interested I could probably find a contact for you in your area. Then message you privately here with those contact details. There's different area branches throughout the country and I'm sure there will be a group In your area? There's no pressure to do events if you join or subs to pay. It's just a great outlet and contact to get involved in different stuff and with great people.