Can't see enough of the rug to tell......................it looks like an off the shelf carpet that has had it's edges bound so as not to fray. Most independant carpet retailers that i use already offer this service, i don't know about the bigger retiailers. You can choose any carpet and they'll bind the edge, and also put webbing on them if you so wish, it's most common use is for stair runners, but the technique can be applied to any size carpet.

I would stick with the rug you have. The larger one I think would cover too much floor and as you say, the corner would be a trip hazard. As for the gap behind the sofa, I don't find it odd at all. It makes sense anyway to allow air to circulate around the radiator. I would actually pull the longer sofa away from the wall a bit too- I know you don't have much room but even a gap of a few centimetres would add to the feeling of space. It's a lovely room. I really like the wall-hung tv unit, very clever!

thanks all! The vanity was made to measure. Just a wooden floating frame which we covered in tiles. Couldn't find a vanity to fit as this was less than 300 deep and about 1100 wide. The tiles we got from a company in Preston called ROCCIA www.roccia.com - they also have a place in Bolton but not sure if they deliver outside of the area. The tile was called Pantheon Marble (antique) by Cerim. Not found any other suppliers. Comes from Italy in all size formats. I got the 300 x 600 and they did them for about £45psqm. Similar ones we found from Mandarin stone were almost identical but didn't have quite as many streaks in. In fact I bought a full sized sample and had to use some of it for the skirting behind the WC and you can't really tell the difference at that angle. They are on sale now so a similar price (they were almost £60 psqm when i looked to buy them!) https://www.mandarinstone.com/product/mimica-sepia-grey-matt/  they are mostly grey but in some lights at a certain time of day, they can have just the very very slightest brown tinge but it's barely noticeable either.

Try your local plumbers merchant. They supply everything but no fancy showrooms.