Question
How long do I keep the papers about a bicycle kept in the hall?
Keep the papers about a bicycle kept in the hall while the thing they describe is still insured, and for a year after that. A receipt is worth most at the point where nobody can remember the year any more.
A bicycle in a communal hall is in the home and not quite in it, and the schedule says which of the two the policy treats it as.
The frame number is stamped under the bottom bracket. It is the detail that makes a bicycle a specific bicycle.