The plan with the Jumo engines is, rather than building entire engines, to install modern rotors in the original engines. I have not heard of this being done before, but I`m sure it`s possible.
And the chances of the CAA allowing them to fly over `ere? Probably zero!

wouldn’t you need to make the combustion chamber out of modern material as well,iirc the orignals were made of welded steel that deformed with use.
also i think i read thet the total life of these engines was about 25 hrs total.
so unless he has a lot of jumo’s i hope he intends to improve them somehow ?
paul