Top tip, smell them in the shop, some makes of cheap mats will make your car interior stink.
If these are ok, a good price

I'd pay an extra £5 or so and get mats that are shaped correctly for your car. Badly fitting matts can be dangerous if they cause the accelerator pedal to snag in the down position.

Thanks OP Tesco sell Really heavy Duty Rubber Mats for about £12, they are Universal fit so you can cut out along lines to make them a better fit for your car. I have bought a set for my last 3 cars and never had to cut them as they follow shape of footwell. If you have Kids you need these, far better than carpet especially in winter with rock salt/snow/ice etc.

Only mats I can see on GSF are £24.48 and £48.53, and they're not custom.

Same here, you would think that all manufacturers would make a standard clip on the rear of the footwell so that mats can be secured..

you can grab some at Aldi for £3.99, I bought some on the weekend.

i've been in a rolls royce, I doubt these are 'ultimate'
but am willing to be wrong

Meh. Spend a bit more and get somewhat fit/don't disintegrate /stink or leave marks. Seriously, why cheap out over a few quid. Some fitted bargains to be had on Amazon.de.