I know a little bit about Potton and would use them myself.
Worth noting that Potton supply the structure and insulation package (plus stairs, windows, roof if requested) it’s up to you to source a builder that will do the light switches and other finishes.
Timber frame doesn’t mean ‘post and beam’, only half of the showhouses even have those because they were popular at the time the houses were built. On the outside, it can have any brick, stone, render, weatherboard you want.
Potton is now a bespoke design and build business, they have planners and architects who design to any style or specification. They fully design from scratch for you, and get you planning, then help you self build with project managers.
The showhouses get a *lot* of foot traffic, so after 50 or so years it adds up to a lot of new wallpapering. That’s not really the point of the houses there.
They are there to show variety and give ideas - and it’s a shame people come away with the idea a Potton house is just a chocolate box with fake beams, if you look at the website it isn’t that at all. Of course at the time it was stylish, but trends move on.
It’s also quite sad that planning officers are judging a company on a style the were popular for some time ago, I would say it’s actually prejudicial and not the correct behaviour for a planner!
Anyway, in my opinion the timber frame you get from Potton is a good spec for a reasonable price in the market, and there’s really nothing forcing you to have beams anywhere.
Check the website, there’s a price list there that breaks down what you might spend on the house and also since you are a total novice, they offer lots of resources and seminars to tell you how to go about it. They are really useful for self builders generally. I found them to be helpful and friendly.