I have a 2' Acer (don't have the exact name to hand) which I planted last
April.
I misjudged how high the sun would get in summer, and it ends up in full sun
for the middle part of the day. Also, I was very ungenerous and only gave
it 1/2" or so or bark chippings for a mulch. Presumably as a result of
this, none of the new growth lasted too long before it frazzled (older
leaves we ok, though)

The obvious answer is to move it to a shadier spot. However, I'd guess
that its roots should be much better established than last year, and I can
give it a good few inches of lovely mulch from the council composting
outfit, and remember to water it more often. Anyone have a feeling as to
whether this would be enough to keep it happy so it can stay where it is?

cheers,
G.A.