... gun outfit of British liner-type troopships? ... very good question ...
On most pictures, hardly any gun is visible. QE/QM carried some AA guns; some sources point at 40 mm Bofors, fitted in the US. Those ships primary protection was their speed.
The slower ships rarely travelled alone, and so their protection against surface attacks was their escort. So my guess, they likely had few or no low angle weapons but a good number of AA-capable guns.