So it would appear my posts on geekzone are now solely focussed on heating solutions and their issues.

New (5 weeks old ) large 8Kw fujitsu floor model.  It's started to smell - badly -  and in particular after we've been cooling in the evening and then using it to warm up in the morning. First 3 to 5 minutes on heating it basically honks like stale footwear, mildew, sweaty socks / gym gear.  That eventually goes but the room now stinks.

Installers came out - he said it smelt like washing that had been left in the machine for a week -  and took apart - drain hose is fine but they did notice a lip on the drain hole that means standing water - couple of mm in the drain pan most times. They also noticed it had two drain outlets - one each end -  and one gets plugged but does leave an inch x inch and a half hole of standing water that has nowhere to go. 

This replaced a daikin of 14 years that looked old and was noisy but didn't exhibit any of these issues.

Googling leads me to many sites ( US based ) that describe it as sweaty sock syndrome but generally its more applicable to units that are a year + old and are growing bacteria.

Any ideas on a fix as the installer quite rightly held up his hands and said " I can smell it " but I'm not sure how we'll fix it.

Thanks again