you should try this as suggested by bossbob:

1). Press Start Button, foot off Brake.
(2). Press Accelerator to the floor, count 20 seconds.
(3). Remove foot from Accelerator.
(4). Wait 2 minutes.
(5). Start engine and drive.

Some people say it’s a gearbox reset, I think it resets the throttle pedal end points and might help with your problem.

I have reset mine following this advice and its like a new car

So after a few days of driving after doing the previous procedure, I don’t think it has actually made any difference.

I may just be being fussy, but it’s good to know this is pretty much normal behaviour for the car. Learned to drive in 2011.
Bought a Micra - great little car
"Upgraded" to Kia Sportage - hated it
Proper upgrade to FL2 TD4 GS 60 reg Facelift - tailgate paint issues, fuel gauge rewire, transfer box failure at 36k miles, clutch at 60k
Reconditioned diff at 70k ish
Sold at 84k and now on a DS. Terribly unreliable.
Sold DS for a 2021 Mitsubishi Outlander PHEV. Fingers crossed....
Sold Outlander for a 2014 SD4 SE Tech because I’m mental

Thanks for the update.
Still unsure whether the procedure you tried resets the gearbox or throttle - or both - or neither? FL2 SD4 XS 2013 Orkney Grey

It would be nice if it gave you some sort of indication that it had registered something. Learned to drive in 2011.
Bought a Micra - great little car
"Upgraded" to Kia Sportage - hated it
Proper upgrade to FL2 TD4 GS 60 reg Facelift - tailgate paint issues, fuel gauge rewire, transfer box failure at 36k miles, clutch at 60k
Reconditioned diff at 70k ish
Sold at 84k and now on a DS. Terribly unreliable.
Sold DS for a 2021 Mitsubishi Outlander PHEV. Fingers crossed....
Sold Outlander for a 2014 SD4 SE Tech because I’m mental

Post following the procedure the car had quicker throttle response and (obviously) got to speed quicker.
So i am unsure if gearbox or throttle was altered or both but it is nippier than before and feels like a car that has 190bhp should.
As far i know this car has never had anything like this done before. As it has improved things it probably needed it and if yours has shown no change maybe didn't need it?

Chuckalicious says
Sold DS for a 2021 Mitsubishi Outlander PHEV. Fingers crossed....
Sold Outlander for a 2014 SD4 SE Tech because I’m mental

Are you sure that you haven't adapted to the 'Electric Motor' instant response of your previous PHEV.
As I understand it the Outlander PHEV has at least 80 BHP of instant power before the ICE Engine/Generator kicks in with the rest.

Your 'Multi Geared' Diesel Fl2 needs a moment to check what gear is required and ramp up the engine.

We may have to 'Reset' your expectations, but enjoy your FL2 return. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

Ian that will be part of it certainly. If it’s what it does, it’s what it does. I just wanted to make sure it was fairly normal.

Despite the stunning mpg for my mileage and the instant torque, I am happy I swapped back to an FL2. Learned to drive in 2011.
Bought a Micra - great little car
"Upgraded" to Kia Sportage - hated it
Proper upgrade to FL2 TD4 GS 60 reg Facelift - tailgate paint issues, fuel gauge rewire, transfer box failure at 36k miles, clutch at 60k
Reconditioned diff at 70k ish
Sold at 84k and now on a DS. Terribly unreliable.
Sold DS for a 2021 Mitsubishi Outlander PHEV. Fingers crossed....
Sold Outlander for a 2014 SD4 SE Tech because I’m mental