hmmm now yer asking
well, i worked for BMA at LHR 1977-85 so often we would have 5 or 6 in at once, they always taxied in on 2 engines, fuel issues were quite a big thing i recall.
re the t/o engine noise hmmmm i really am sorry i cant remember,
at LHR my office was on A9 on the ramp close to the runway i/s where often our VC8's would sneak in for a short take off BUT the noise was usually drowned by a trident taxying past!
i used to go to SEN alot in the 60's and 70's to watch channel airways vc8's too..
i obviously flew in BMA ones dozens of times both in the cabin and on the jump seat but i still dont recall an engine noise dip on t/o after initial power going on....
love to go on a viscount now sigh