Slb,
As in all aspects of life, there is a right way of doing things, and a cheap way of doing things!
When a client awards you the cleaning contract, they rightly expect a good standard of service, value for money, and that you, on their behalf, act in a safe and proper legal manner, after all they have awarded you the contract because you are the expert!
Key loss, is not covered as standard on 95% of insurance policies, and as you have found out, there is of course an "additional premium" for this cover, however, the client would not be happy if you indeed did have the misfortune to mislay their keys.
Steve's suggestion maybe ok, at a push, providing the premises is a very small office, perhaps 5 or 6 people working in there, but any more than that, and I would insist on the cover.
Lots of buildings these days have fobs for the alarm, if you get say 10 or more employee's within the premises, thats an awful lot of fobs and keys to replace, 10+ locks, 10+ fobs, bit more than £1000:00 me thinks, as a matter of course, your client would have to inform their own insurers of the loss of keys, in case they invalidate their own insurance, in my opinion, they would not be interested in you saying"not covered by my own insurance/I havent got that kind of money"
Darwin Clayton, specialise in comprehensive insurance, certainly not cheap, but again you get what you pay for, and this sort of protection can be used as a selling point to your prospects, and as a way of fighting the cowboys out there.
Regards,
Rob