Hmmmm.... see y'all like to take the piss out me for having been a tradesman but it saves me a bomb with stuff like this. In your situation I'd only be looking at the cost of the parts
Anyway, as I always say to anyone in your situation, be patient and DO NOT engage with the AAAAAAARDVARKs. The will totally rinse you in addition to being dangerously incompetent.
I can come round and do it for you if you like Ash. It won't cost you much but I will expect to have s proper go on your missus.