I have two GO720 devices, both still work well enough but on one I use a large map of Western Europe and the hardware shows its limitations on roundabouts and complex junctions by not rendering fast enough. It causes me some jitters if roundabout exits are close together and against best practice I do rely on the screen during complex junction transits for a quick glance at where I need to be.
So I would like a recommendation or two on a good second hand newer faster replacement, I would be leaning towards something that I can see as a Windows drive rather than have to learn new procedures using software tools not available to me, seriously I still use Win7 and it does all I need. So my options are obviously limited but I do need something that handles big maps better.
TIA.

I’d say that if Windows 7 is still working perfectly for you, there’s no need to worry about a TomTom from the distant past.
I know the problem all too well; my old TomTom Rider v2 had the same issue—on winding roads, it would often lag several turns behind. That’s a thing of the past with the Rider 550. It’s time to upgrade; after all, the milkman doesn’t come to the door with a horse and cart anymore either.