Best try and find somebody to come service it then as the bloke who serviced it last doesn't seem interested in coming to do it again.
From reading on here it appears there is a repair kit for diverter valve so i best get that ordered and fitted
Still been quiet new to this house lark am wondering how often a combi boiler should be serviced,
We bought a repo 4 years ago and once we had finished house bashing and fixing it up. we refitted all radiators and pressurised central heating system and had boiler serviced before we used it...
Get yourself over to briskoda forum,
Some lads on there that know octavias inside and out,
If it has sticky vains then if a good thrash doesn't sort it then it could get expensive to fix