Thanks for the advice, looks like a rower is the answer. As I live in the north of Scotland outdoors exercise at this time of year can be difficult (pulled muscles due to the temperature!). Swimming as you say would be ideal, but the facilities are generally a) expensive and b) in use by local schools. Come the summer I have hundreds of hills to walk up, but for now I'll imgaine I'm rowing somewhere warm!

Cheers

Gav