Baxi Boiler problem - grating sound

Hi,

Recently my boiler (Baxi Solo 2 model 40) started making something of a loud grating noise when firing up, which continued as the boiler ran, and ran down within a few seconds of the boiler switching off (actual boiler operation is fine, BTW).

This volume of this noise has since reduced, and now sounds very much like a moaning-grating noise, but is *fairly* quiet.

I've had the carcase off the boiler to take a peek inside, and the sound seems*1 that the sound is coming from the fan unit (unit is described as "fan assisted" - I guess that means a powered flue?).

One thing I noticed is that on top of what I'll call the "blower" - an encased cylindrical unit that I assume holds the hot fan, there's the exposed drive motor, and a small pressed steel fan blade, presumably a secondary fan to keep the motor cool. If that is rotated by hand it actually lightly fouls the "blower" assembly. This in itself is not enough to cause the noise, but might be indicative of a bearing collasping, resulting in the shaft being off-centre.

One further observation, it's getting hot around the blower unit - to the extent where plastic shrouds around electrical terminals are disintegrating.

So, quick questions....

(1) Does this indeed sound like a fan/blower failure.

(2) If so, is this a DIY or professional job?

(3) If DIY, typical cost of a fan unit? (all I can get ATM are details of places, not prices, and I need to diagnose the problem 1st)

(4) On a 7 year old boiler, is a replacement unit more practical?

(5) If I was to replace boiler WITH LIKE, installation / commissioning charges likely from a Corgi?

Thanks for bearing me out

Regards

Mike.