Thanks for your inputs guys, it's really nice you're trying to help me with this cotter issue (kind of classic one!).

I think I will go for the cotter pusher solution, i.e. going to a cycle shop in CPH I will just try the one at the corner. With some luck, it can be at cheap cost.

I am aware cotters require hand filling! But thanks for reminding me, I learnt it quite recently.

Regarding the fork....I see what you mean but I had a proper look to it and it seems OK. No "bent" signs or fragile parts....It might be the original shape! I think the frame is in OK condition.

Cheers, Ben