No, a complete major has been carried out. Certain structural work has been carrried out to extend the aircraft life to the planned final flight date; the engineering team have kept close to the anticipated schedule and that side of the project has gone well.
I950s-60s electrics and hydraulics are far from being as benign as your post implies! 4000 psi hydraulics, large moving components such as landing gear - all to be restored in an expensive 21st century 'Health and Safety' environment...... There will be more setting up work to do when the engines are run - trying to get 4 AC generators to paralel properly is often tricky in a VC10, in a Vulcan the alternator trimming has to be done externally and can be more of an art than a science!
Most of the antique avionics are being replaced by more reliable, modern systems. But all such work has to be thorough and to normal standards, if the CAA is to let the aircraft fly.
I very much doubt whether the 'man in the street' is being taken for a ride. Certain costs, to me, seem surprising - such as the rent of the restoration hangar - but, overall, this is a hard working team trying to realise their dream that others may yet see the majesty of the Vulcan in flight.