Had a look at the book - the reconstruction programme was from 1926 to 1929, with works finishing in 1930. 230,000 bricks from the original structure were re-used.
In the major restoration of 1984-91, many of the inappropriate changes were rectified such as replacing concrete castings with Portland, which were unaffordable in the 20s.
Albeit a near total reconstruction, the north front is still my favourite - I have a soft spot for flat porticos, and the statuary perched on top give the charming impression of being on display on a mantelpiece, especially with the top storey behind. This central part, complete with deep arches is a magnificent piece of architecture, and much more interesting than the south facade - while impressive and exquisitely proportioned, I think becomes boring rather quickly.
And the tall and narrow drum of the dome looks out of place when viewed head on, a problem confounded with the new dark stone, which merely highlights the issue and further detaches the structure from the rest of the building.
I got the book recently you mentioned dc3, there's one copy left (bit battered) in Hodges Figgis, where I scoured every shelf in the place till I found it in a darkened corner!
It notes that Gardiner St was laid out where it is purely to allign with Beresford's apartments on the north front - and considering the vista of a bit of the rear-end of the dome is far from planned for the street's benefit, this would appear to be the case.
Very few people have been inside to the Visitor's Centre, it's worth a visit, the carved Bath stone is so crisp and perfect, and the views from inside under the south portico to the river are extraordinary. Think it's â‚¬2 in, and free for students.