I have an 18 year old Baxi 105e which is becoming more and more unreliable therefore I've decided it's time for a change. The house is a well insulated modern bungalow. I'm considering changing to a Ideal Logic boiler. All the pipes to the boiler come from above due to the construction of the house therefore the existing boiler is mounted on a standoff. The flue is side mounted rather than rear mounted and the existing centreline to the flue is around 200mm from the rear wall. Is is one of the major advantage of going for the Ideal Logic as inclusive of standoff the centreline to the flue is 200mm, therefore greatly reducing the work required during installation. I guess my big question is, which size to go for, the C30 or the C35, I've been quoted both. would either be a satisfactory replacement? My main concern is underspecing the boiler. Anyone have any advice? There are 10 radiators on the system 2 off 1400x600 doubles, 1 off 1200x600 double, 1 off 1000x600 double, 1 off 800x600 double, 2 off 800x600 singles, 1 off 400x600 single and 2 off 1200x600 towel rails.