This is all well and good but its a bodge at best .The manifold will be full of crap it needs removing and cleaning, in my opinion I would replace it .The car will run so much better, you need to delete the ERG as well this will stop the crap building up ever again .
This was done years ago now , granted it is not as good as a new manifold , or is it ? With a new manifold I will still have the worry of swirl flap issues lurking , this way I don't .
I disagree that is it a bodge , It is purposely done to stop the swirl flaps moving and make them redundant ( I didn't actually do it cause of carbon build up ) - so it is no more of a bodge than other ways to delete or negate them , the same way as people delete dpfs etc , none of these items benefit the owner of the vehicle and it's longevity and durability.
Car has had egr partially blanked , gets diesel cleaner every 6 months or so and runs a regular dash or mineral 2 stroke in the fuel . I don't regret saving the neck end of a £1000 at the time and it still runs like a train (sounds like one too ! lol) and I am happy.
Later thought - You state about EGR delete , I agree it is definitely a good idea . When the car was remapped years ago there was not the option for EGR delete , this may be something I would consider for the future.