I quite like my lawnflite mower, it makes pretty stripes (I know not one of your requirements).
It’s got a Briggs and Stratton engine which is ok, but compared to the mountfield I had before (the deck rusted away but was already very second hand when I bought it for £20) it’s harder to start, and I don’t think it’s as strong when ploughing through grass that’s a bit longer than ideal.
So I think with a bigger budget I’d look at something with a Honda engine, and not with a metal deck. I paid about £350 for mine because I wanted one that had a roller on the back instead of wheels.
I went to a few shops before buying and one of the other mowers in the frame was a Haytor, and all the shops said they’re over priced and not what they were – so perhaps avoid that make.