Having lots of properties is not an excuse for not complying with the legislation. Imagine if some large company insisted that they had so many staff surely they cannot be expected to give them all protective workwear where required. Do you reckon the HSE would swallow that? I am being slightly antagonistic here, because I would not expect everything done at once, however I would like to see something more solid than "we will do it when we get round to it or when we do something else"
As far as enforcement goes, Article 8 would suffice, linking it to meaning of general fire precautions:
(a) measures to reduce the risk of fire on the premises and the risk of the spread of fire on the premises;
If the premises was not operating as stay-put then article 14 would do, means of escape.
As we are all aware it is up to you/them to prove it is not reasonably practicable to do more than was/is done.
Quite right CivvyFSO
As ever communicate with your local fire officer, agree a suitable and reasonable timescale to get failings or deficiences rectified. If its got to be done, then its got to be done, the issue wont go away just because there isnt enough cash to sort it!.
An RP shrugging their shoulders and saying " cant do that cos I cant afford it" is not acceptable, instead enforcers are looking for the RP to say something like " I cant afford to replace all the fire doors this year, however i will do 50 % this year and the remaining 50% next year" or whatever it may be.
Fire Officers generally are reasonable people, but you have to give them all the facts so that they can assess the overall picture and decide (along with the RP) what is a reasonable timescale.
The order applies to large companies just as much as it does small.