I'd recommend a Nextbase 422GW or 322GW. The GW stands for GPS and WiFi, plus I think the 322GW is on offer at £90 on the Nextbase site at the moment. The Nextbase I've mentioned does come with some extra features you might not want, but I'd still go for that one as it offers some great features — including Parking Mode, high-quality footage (above 1080P), and time, date and speed stamping so you can use it as evidence if you need it for an insurance claim. You could go for the less expensive option (the 322GW) and then get a proper dual dash cam (the front and back window that record onto one memory card) if that's something you're interested in. Nextbase does the 322GW with a rear window module but the module itself is about £50 I think. You'll also get a warranty with a Nextbase cam.

I'd suggest following this link as it'll take you to Nextbase's site so you can directly compare relevant dash cameras in a very useful, easy-to-read table: www.nextbase.com/en-gb/compare-products/

Another thing I'd suggest is searching YouTube for some footage of the Nextbase 322GW and 422GW so you can get a look at the quality of the footage. Remember, in a worst-case scenario, you'll need to pull the footage in order for it to be used as evidence for a claim — so you need something that can read number plates (even in the dark and bad weather). Youtube has tonnes of dash cam videos so I'm sure you'll find a few, just remember to adjust the quality settings on the video so you can see the footage at its highest quality — i.e. 1440P instead of 1080P, which Youtube tends to drop into automatically in order to compress video and play it without buffering.

A final note is that if you want to hardwire the dash cam (a popular option and fairly cheap at Halfords), then you may need to alert your insurer as some of them consider it a modification that can result in a voided policy if not mentioned. If you really don't want a Nextbase for any reason, take a look at Garmin's dash camera range instead as they're also quite good.