My Heritage DNA tests

[Merry]

I have a contact who has issues with his tree because the parentage of his maternal grandfather is difficult to prove with a high level of certainty. A while ago I suggested he do an Ancestry DNA test to see if that would help.

Now, a year or so later (!) he has done a DNA test, but with MyHeritage instead of Ancestry I am not familiar with MH at all, so have some questions:

Am I correct in thinking MH results cannot be uploaded to Ancestry.

Should he be getting worked up that his results through MH show him to be 25% Italian when all the paper research done so far has shown him to be from London/Surrey/Oxon on both sides of his tree back to all gg-grandparents (could possibly be errors in the maternal grandfather's line, but I don't see any sensible chance of Italian blood in any line unless someone pretty close to him has the wrong father on their birth cert, or similar. How accurate are MH results? Could there be issues with them not having such a large database as Ancestry?

We have big internet issues at the moment, so I am having to use 4G from my phone to connect. I can't use that too much or I will run out of 4G allowance, so apologies if I don't reappear as often as usual!