Premier Inn (and Travelodge) are the hotel equivalent to budget airlines (OK, a little overstated, they don't have the array of hidden charges). The business model is keep it simple, keep it standardised and do most contact online with no human involvement. Like the budget airlines at times they have ridiculously cheap online offers, and when things get busy they can be as expensive as the full service hotels. They have rooms which are very similar (if they are new builds they could be identical from town to town). You get a room, a decent bed, a TV, a shower room. Breakfast is normally optional and usually in a pub next door which is owned by the same company, if there isn't one they have a small bar area where limited food service is available. Big city centre locations may not have parking but most do. And that's it. No laundry, no room service, no bag carrying, and probably no experience from the "duty manager".
The premium rate phone numbers in the UK serve two purposes. Even if you have calls included in your phone contract you pay extra for these numbers, and as said they may not be available from outside UK. Reason one is that the number is for a service, typically someone you can call to ask advice and sort out your problem over the phone, you pay for the advice through your phone bill. The other reason is to persuade people to stop phoning them and to use the internet for automated queries!!! These numbers have non-geographic area codes in the ranges 084* and 087* and you can try to find an alternative at this site
https://www.saynoto0870.com/companysearch.php If you find a number, bear in mind that if they were using reason number 2 you may not get any sense out of them!
note that 0800 and 0808 are free calls (but may not work outside UK.....) 0300 is believed by many to be a premium code but isn't, it just doesn't have a fixed location.