@Hollie there aren't many seats that are isofix OR non isofix, it's usually one or the other, or both! In fact I can't think of any at all.
It depends on the child height and weight and how old they are. You're better off asking in a car seat group for specific recommendations
@Hollie babyauto is not a recommended brand, they don't do any testing beyond the minimum required and promote rear facing at a very young age. Their seats are also all isofix fitting (apart from the infant carriers which is the same as any other brand, and the taiyang which is seat belt only)
Joie stages is one I regularly see recommended
I just got a Graco R129 for my husbands work van, seems great and suitable from birth to 12 years as converts to booster. Was £130
We've got an avionaut pixel Pro 2.0 infant carrier that cam be isofix or seat belt abd absolutely LOVE it.
Is it infant car seat or 2nd stage