I don't think we'll get many 'British' brands, maybe some roaming characters and Harry Potter.
I really think a lot of what we'll get will be copies of the other parks, perhaps with a different ride system, like they've done in the parks in Japan, Singapore and China.
Things like Jurassic Park, Fast and the Furious, King Kong, Minions, Harry Potter, Transformers seem likely to me, perhaps a Nintendo World too?
Would obviously love for some more unique IPs
Current rumours suggest that Universal are looking at different rides and IP to differentiate the new park from the Orlando resort and avoid cannibalising their UK vacationers market. The no Orlando clones rule in particular is one that's been thrown around quite a bit. (Wrote most of this before seeing crazycoaster's post so yeah, echoing what they said a bit here)
For Jurassic that seems fairly straight forward, as they can just clone the Beijing ride and kids area, then plonk in a unique thrill coaster somewhere. (A new gen vekoma flyer as a successor to Japan's flying dinosaur please!)
F&F seems like the perfect candidate for the second thrill coaster as Hollywood Drift feels unlikely to be arriving at the Orlando parks any time soon. Minions and the DreamWorks properties already have a presence at Orlando (or will do within the next year in the latter's case) but will be good draws for families and have the potential for unique offerings.
The property that I personally want the most is Nintendo but that sadly seems unlikely with Orlando already planning to cover all of their most popular series. The one exception I can see is Pokémon - if the ride rumoured to replace the Simpsons in Orlando is different to the Spiderman retheme Osaka is supposedly getting, then I can see Bedford getting a clone of the Japan ride, maybe as part of an area set in Galar (the region based on the UK from the recent Switch games). Pop-up Pokémon stores and events in London have been rammed so there's clearly a demand for it over here.
Potter feels like it should be a shoe-in, but that may depend on what they can create without repeating what already exists at either Orlando or the Studio Tour. Maybe a revival of past concepts like the Knight Bus or the Weasley Bros' flying car?
I could see a smaller Potter zone work particularly well as part of a larger "London Waterfront" area near the front of the park, halfway between a hub area and the "UK IP land" Chris mentioned. I'm picturing a covered main street, similar to the Japan and Beijing parks but with a Covent Garden style shopping arcade feel to it, with a mix of regular main street fair and some more wizardy bits like a bookshop or a food location. At the end would be a larger area facing the main lagoon, with a theatre for a Bond Stunt Spectacular, some sort of UNIT base that could lead to a Dr Who ride*, the aforementioned Potter Thing and paths leading to smaller areas like the street Paddington lives on.
Either way, I think utilising some UK IP would be a smart move. They might not have quite the same weight as some of the American brands but they still have a decent pull to them, and with the number of Anglophile tourists London already attracts, making the most of the unique culture here might help sell the park to more people. These are franchises with legs too - Doctor Who and Bond have both been going 50+ years and while they've had ups and downs they've proved adaptable enough to keep going. Then there's LotR. Regardless of how well the sequel series goes, people still come back to the original movies and travel all the way to New Zealand to visit Hobbiton. The potential for an immersive area in that world is super exciting, and I can see a Middle Earth area serving as the parks unique star attraction.
*Disney be damned, I just know Universal Creative are itching to have a go at the Bigger On the Inside illusion, plus Disney don't distribute Dr Who in the UK nor have any theme park presence here so I don't think it'll be a massive issue.