Why three threads?

It's not baffling at all - drivers in the first year have a very high rate of accidents which is reflected in premium rates - insurance companies can see how those accident statistics are affected by overseas drivers coming to the UK.

It's not baffling as RT said. Newly qualified drivers especially young ones are much more likely to have accidents. A friend tried to get insurance for his son who'd learnt in his mk2 landrover iirc it was about £1700 for something like a 15 year old 1 litre Fiesta.

On the other hand the high prices could be a reason there are so many uninsured drivers around.

The OP is lucky that theirs is 'only' £1100. I've heard many instances of that figure being 2 or 3x as much, even for basic superminis, often because the new driver is just 17 and/or that they live in a high vehicle crime / high accident area.

The most I paid was around £640 about 20+ years ago when I was still a new driver after my 'introductory offer' with RAC insurance locked me in to staying with them, whereby they bumped the initial decent price of £350 up three years in a row. That was for a basic 1L Micra.

With inflation, £640 is around £1100 - £1200 today.

If I were the OP, I'd concentrate on getting the most reliable, basic spec car they need (not want) and can afford (including pricing in premiums for 3-5 years at similar rates, declining a little) and driving carefully, gaining experience and avoiding accidents.

They may be lucky that some 'nice' manufacturer is running a similar lower cost insurance plan, but beware of being effectively locked into staying with them and enduring significant rises in their annual premium or leaving and having to find the money for even more expensive policies elsewhere.

The trick is NOT to have any fault claims. I had one smallish claim in year 2, and even though the policy was PNCD, it didn't matter a jot when finding alternative providers, because it was how many years of actual no claims I had. IMHO, I was mis-sold that original policy as I naively believed the sales speil saying I could 'take' the PNCD across as '5 years' when in relaity I could not. In my defence, I was a lot younger and more naive back then.