It would appear my sons 2009 1.3 Diesel has suffered a heater matrix failure. Has anyone here undertaken the task, how complex is it?

He's had a telephone conversation with an Alfa specialist and they have suggested that it's a dash out job and have given an estimate approaching £1000

Hi, what failure ?
Eventhough it might not require a full dashboard removal, the heater matrix replacement will indeed need a LOT of dismantling ! I'd say a DIYer could do it on one saturday in its garage, assuming he's got some skills and basic tools.

The eLearn CD is a MUST aswell as it contains the procedures to dismantle hose, piping, vents etc. around the exchanger (but not for the matrix itself!).
1000£ might seem a lot of money, but it's also the price of tranquility and if that includes the replacement matrix and is garanteed I'd tend to say it's not over exagerated ...

Cheers, Bernie