Hi Paul,
we do alot of care homes and they always want something for nothing :
That sounds like pretty fair area to do though and care homes are normally hard work and haven't been cleaned regularly.
I wouldn't guarantee getin rid of any odours as the smell can easily be in the floorboards and other furnishings, one home we did had to actually rip out the floor to get rid of the bad smell ( but thats another story )
It depends on how desperate you are for the work, £600 is £600 in the bank, but you don't want to undersell yourself, we probably wouldn't touch it for less £1200, but then were not too hard up for work at the mo.
It makes me wonder why she's already told you the price of the previous quote, most business people won't do that, unless they particulaly want you to get the job! - She may be stringing you along, sometimes they have a fixed price in mind of what they want to pay.
If it was me, i would go and do my normal survey and sizes and explain the reason for your price and what they get for it!
Believe me it will be hard work.
regard
steve