Well, after a few days of experimenting with different gear ratios, the chain broke again! I think I've found a setting I'm happy with but now I'm starting to have doubts…
I'm confident a single-speed would be fine for my commute, but I've started to take the bike out at lunch time and in the gear setting I've settled on, some parts of the uphill journey are pretty tough, and the longer stretches leave me spinning a bit.
There's a C2W scheme at work that would allow me to get a bike for not much a month (and some servicing) and I'm debating going for that instead (and giving the Raleigh to a good home).
What do you think?