Am desperate.... Smell of mouse

[Eshermummy]

I noticed we had mice in the playroom a few weeks ago. I put down poison feed in bait trays (have used this method before) and thought I had got rid but there is now a really horrible smell in the room.
I'm not sure if it's the smell of live (urine? Faeces?) or dead mice although am not sure the smell is rank enough to be a rotting dead one???
What can I do? I have had a couple of loose floorboards up to look for a dead one but no sign. I put some of those neutradol smell absorbing solid fresheners under the floorboards but it only maske the smell and tbh is just as bad.
The floors are wooden and very old and gappy (which is how they get in) and have been cleaned with usual cleaning products - should I use a bleach solution?
I haven't seen any droppings btw.
I have got 30 people coming for a drinks party this Thursday and I really want rid of the smell by then..... Do live mice have a distinctive smell or is it a dead one that is hidden somewhere under the floor (not sure how I can solve that....how long will it take to finish decomposing?)
Help!!!!!!

It all depends how sensitive your nose is but generally a mouse smell will be a decomposing one. How long it takes to go depends on room temperature, if reasonably warm it may be gone by Thursday, but any dead mice I smell tend to be brought in by my cats so I usually locate them and dispose of them.

Hmmm, well smell has been here for about a week now. It's sort of sickly sweet and musky - not really rotting as such. The house is old (160 years) and underneath the floorboards there is a cavity then bare earth iyswim. We have air bricks at under floor level on the inside that are soil level on the outside iyswim. They are apparently needed for adequate ventilation - airflow seems to be good as when I lifted the boards I could feel the air running through and there is no damp under there.
I kind of assumed it was linked to the mice but if it's not them what else could it be?

Sounds like rotting mouse. My cat brings them in and that's when I know to look under the appliances when I smell that musky sweet yucky smell. I think you'd be looking at weeks for full decomposition underneath floorboards where its not especially warm. Our utility room (where the mice are left) is also not especially warm always and it takes a few weeks to notice the smell and it can also linger despite washing and bleaching the area. Probably made worse by urine and mice poo - mice leave an AWFUL lot of poo. I think unless you can get under the floorboards and remove carcasses and poo/wee then your best bet is to mask the smell with air freshner - one of those one's where it plugs in and emits might be your best bet.

mouse poo stinks and the smell will last until it dries out, up to say 6 weeks maximum. if it is mouse poo causing the smell and the smell doesnt go it means you havent got rid of all the mice!!!

if it is a dead mouse you will soon know as the smell develops into an utterly disgusting rotten mouse smell!!