So looking some more at the specs these are some differences which I would like to understand...
30Cdi:
Condensing in DHW mode. What advantage if any does this give me?
Thought that would be obvious .Cheaper hot water production. So if you use a lot of hot water then the savings will be much greater also get yourself the DT10 RF stat which enables you to time the Eco function of the CDI rather than just having it either on or off,best of both worlds really.
CDI is a brilliant boiler ,only one I would fit to my own house now.
If you go for a WB AI (approved installer)you will have either three or five years warranty as standard with either of these boilers and the AI can purchase four years WB servicing for you at a nominal cost. Two additional years' warranty and the four years WB servicing cost the WB AI £215 +Vat.
Thanks for all your help. I am using a WB AI so am getting 5 years warranty included and he already included the DT10 RF in the quote too.
I will have to ask if there are any servicing packages I can also opt for.