Frazw,
What problem could your bike possibly be causing for the means of escape for people in the building?
There are two groups of people to consider.
The first is people who resort to the crawl space accessed by the flap above your bike. Generally, means of escape from such places is not even considered by anyone carrying out a risk assessment because:
1) they are resorted to very infrequently,
2) when they are resorted to it is the responsibility of the person going into the space to ensure that they have their own personal satisfactory means of escape.
The only way you could cause a problem to these people is if someone goes up into the crawl space when your bike isn't there and then you come along and plonk your bike down in precisely the spot where it makes it impossible for the person in the crawl space to get out. You wouldn't do that, would you?
The second group to consider are the people who normally resort to the more accessible parts of the building. For example, your neighbours or their visitors or you, yourself, or your visitors. You would cause a problem for such people if you obstruct the normal route of exit in the stairway. Don't do that and there is no problem.
Simply. just ensure that your bike isn't causing an obstruction and no problem exists.
I'm assuming here that your bike is not built of highly combustible material!
Stu