I don't think there are any UK GT models. All 2020+ rockets are assembled in Thailand. Only TFC models are assembled in the Hinckley Plant. If you are looking to own a UK made Rocket then you might be in luck now as they are thinking of moving the production back to UK.
"Only TFC models are assembled in the Hinckley Plant. " per my dealer, my bike (2022 GT) was assembled in the UK (hence fast delivery - only took about 2 weeks)