Thanks for the tip re paint pens. I've dealt with normal BB's before but never cottered cranks and have neither the tools nor experience! Luckily it feels smooth and gives every indication of being serviceable, unlike the front wheel which needed stripping down and re-greasing. The quill stem is absolutely wedged in place, which is annoying as the headset could really do with a service....

Having looked again at the mudguards/fenders I think you might be right - perhaps I'll give them a try. If they end up spoiling the finished bike then I'll repaint as and when I have the time.

The following chain-guard is due shortly and will be stripped down and painted to match:

(ebay pic)