Leak under the bath - replace the floorboards?

Elphaba2007

Hi, (long sorry)

I moved into my house last year. Some time before we moved in the old occupants had a new bathroom put in. It looks beautiful.

Unfortunately last month it was noticed that the bike shed (almost directly below the bathroom) was totally soaked. I'd noticed before that that it was damp, but I just thought it was because it was winter and raining and we're always getting our bikes in and out. But last month the whole floor was sodden.

Got the plumber round (he's the guy who installed my central heating and did an excellent job - not the person who originally installed the bathroom). Turns out there's a leak from the mains supply to the cold tap on the bath. He reckons it's been going on ever since the bathroom was installed and all the floorboards were soaked (old wooden ones), and the plaster behind the bath blown.

So - he's done something to the cold tap so the leak is stopped. We can still have a bath filling up only with the hot tap, so it's ok in the short term. But clearly it's not ok if we come to sell.

The trouble is, the way the original plumbers installed the bath means that access to the taps is a nightmare. The taps are next to the wall (far side of the bath), the bath is boxed in by tiled boxing on 2 sides (I don't have enough matching spare tiles to retile the boxing), the bath is also bolted to the wall underneath other tiles that would need removing, the sink is in the way, there are old pipes behind the bath that the original plumbers just left there, and also the bath is a spa so the spa pump and pipes also make things awkward.

The good plumber reckons it would be possible to cut up the current bath, and replace it with a new one without doing too much damage to the boxing and tiles - mainly because our current bath is slightly larger than normal, so a new smaller bath should be ok to install. This is the cheaper option.

However, he also mentioned the possibility of claiming on insurance and getting the whole floor replaced since the boards have been lying soaking wet for a year or more (they're drying out now the leak's stopped). This would mean retiling the entire bathroom too, due to lack of matching tiles.

So the question is - what is the danger of doing nothing to floorboards that have been wet for that long and allowed to dry? Should they be ok? Will I get dry rot? Do you think they need replacing? I have no idea. Any recommendations appreciated. I'd like to avoid the need to replace the entire bathroom if possible, but obviously I'd rather avoid rot! Is rot in these circumstances a big risk?

Also, anyone know how much house insurance premiums are likely to go up if I make a claim?

Thank you!