Hi Crab,
It is normal to use ALT.A for 2D approach (provided it is not CDFA) but normaly only in 4-Axis mode, to capture a MDA/H.
I also spent a year when the DECCA+Moving Map was still the primary area navaid on a couple of our 61s.
Going back further, Gazelle AH1 SPIFR with no SAS and with Doppler mini-TANs in the BAOR IF Corridor...………..
So I will see your DECCA and raise you Doppler Mini-TANs which was as much use as tits on a fish!
We keep going until we get to a magnetised darning needle in a pool of the co-pilots piss and a hand drawn map from a Pirates stash!