D5 (2005 on) 2008 Volvo S80 D5 deep rasping/sporty exhaust sound wehn col

[Volvo444]

Bought a car and all seem fine, didn't use it for a few weeks due to lockdown and when cold, during the summer and winter. The exhaust sounds louder than I think it should, especially during the first 5 minutes from starting and the acceleration is just not there. Is that a turbo issue? when warm it is more a rasping sporty exhaust sound, not as loud as when cold and it picks up speed much better when accelerating to overtake.
It also starts a bit rough for a minute as if one of the glow plugs isn't getting warm.

Also the fuel economy is really poor, only getting an average of 32.5mpg which has gone down from 33.5 mpg even though I do a 12 mile journey to work and back.