Hi Andy P
I got my 145 Cloverleaf the wednesday before you! I think the best thing to do is get it checked over and fix the annoying problems it might have. My one has a mass of intermittent electrical problems, headlights going off, indicators not working, clock, hazards, brake lights, alarm siren! I think it's all fixed now with a few new fuses and cleaning of lots of terminals.
If you've not had an oil and filter change on it then it'd be an idea to, it's not hard but you can't count on the stuff that's in it being any good. Check the tyres, brake pad wear and the general condition of the car. If it's approaching 72k miles then it'll need a new cam and probably a vavle variator/cam belt tensioner.
Take it easy! I've just moved up after driving minis for the last 17 years and it feels like i'm driving a rocket ship! Good fun but not as chuck-aboutable as a mini.