176k is relatively low miles for the sort of use you give it imo, it's had a fairly comprehensive overhaul by the sound of it and should be good for another year at the very least.
It seems pretty daft throwing it away for peanuts when you've shelled out on sorting it out tbh, and I can't see a Mk1 Focus being any better, if anything, it'll need the same again sooner or later anyway.
If anything, I'd consider sourcing a replacement interior for it (most private hire cars suffer here) and perhaps give the bodywork a refresh / touch up if its required.
If the engine went bang, replace it with one from a breaker...
In short, it owes you £3k, get the money from it by working it, don't throw it away on something else, at least not yet.