Or should I be getting 32Mb on my current package and I in fact need to investigate an issue?
A number of factors will be affecting the speeds you can currently achieve.
Not least is the distance from the fibre cabinet.
Do you have a rough idea what that distance is?
How often the connection re-syncs can also have a major effect on how DLM sets sync speeds, as can cumulative error counts, copper or aluminium cabling, time between errors, noise interference, crosstalk etc...........
I am situated "up to" 1000m from my cabinet, currently in sync at 29.6Mb & have occasionally synced at up to 35Mb & as low as 7Mb when my connection had major physical issues.
FWIW, My original estimate was 14.6Mb (original 8c profile) & I achieved a stable 35Mb sync speed for almost a full month.
Profile 17a was introduced in October 2011 on my connection & my estimate went up to 24Mb.
My estimate has been 30Mb for the last couple of months.
My ISP put me on the 80/20 trial just as an experiment to see if cabinet output power could be automatically increased for the higher frequencies that MIGHT have improved sync speeds.
This experiment proved just one thing:-
Sync speeds were not improved at all

& I am now back on the 40Mb service, at my request.
HTH.