Just been to Apple Store.
I booked in with the Genius Bar on line.
Battery replaced free of charge, without question. Thanks.
Computer checked and no obvious faults - so I'm just cleaning said computer and re-loading the system as suggested by the Mac Man.
Hopefully by the time SWMBO returns all will be working!
It is good service and a friendly environment at the Apple Store - everyone seems genuinely interested and the punters all seem knowledgeable and keen on the products.
Smiling again.
FOK