[Spiderman]

"reasonable" is the answer here buddy. Personaly i think its reasonable to expect that but dobnt take it as a given.
I think the fairest way forward would be to suggest to your landlord that he does not charge you rent for those days you are out of the house.

After all its unreasonable to expect you to sleep in a room that smells like a sewer and thats nto the contract you have with him (to rent a room that smells like a sewer). However, should he be expected to pay for you to stay in the Ritz? No, clearly not.
Is the rent you pay roughly equivalent to the cost of a cheapo hotel room? Well knowing you live in Camden i doub it, even the cheapest tTravelodge room is about £30-35 per night and if you pay that much then mate i got a room you can rent off me at those rates, lol.

I'd suggest you first ask your L/L to pop by and smell things for himself and take it from there.

Feel free to PM or call me buddy, the G/F is head letting consultant at an agency up in Hampstead too so we got your back mate.