Lack lustre Power vs engine Revs

[Malt56]

Hi, looking for some advice/suggestions regarding transmission power loss. I have a 2008 2.2 cdti 6MT car which is due to have front struts & drop links replaced, however after just completing a 400 mile round trip, I became aware of a potentially more serious issue which may nullify the suspension fixes. The car seems to struggle, I can shift gears without issue but depressing the accelerator while raising the engine revs does not seem to translate to increased acceleration. Also noted that when the car encountered a change in load ( eg going up a hill ) , depressing the accelerator pedal, I can hear the engine revving but the car seems to struggle - it eventually gets there but not as responsive as it should be. I have read some posts regarding US auto models which seemed to suggest that issue could be as simple as transmission fluid clean out and refill - does this sound correct ?
I first thought it might be a clutch issue, however not aware of any slipping of gear bite through the gears.
I also do not believe my suspension issue would cause this poor transmission response. - Is my assumption correct ?
My MPG value also increased during my round trip - so does not appear to be an engine efficiency issue.

Used my basic Torque application to check for any faults real or pending - nothing reported ( although tool does not access all ECU's in the car).

Any of this sound familiar - advice & potential cost of repair ?

[Trevor]

I cannot think of any particular reason that the suspension repairs would have any bearing on the transmission performance.

Therefore, it must be a transmission (or engine) issue.
If the engine revs freely then I would be looking at changing the gearbox fluid and filter and go from there.