We don’t have contents as landlord has that
I am presuming from this the landlord lives at the property with you?
If so ask him/her to add your bike to their policy as a listed item and offer to pay the increased premium/expence for alteration to policy and you should be all good.
Otherwise his/her policy will probably not cover your things just the contents listed in the inventory of the property. I have used Endsligh in the past for insuring contents only and listed my bike on the policy, there are other insurers out there that have policies designed for students that are available for non students in rental properties.