CT wrote:
I was given an Acer Palmatum 'Garnet' a week ago, but it has some leaf
scorch[1]. Over the week it seems to be getting a little worse. I
suspect it's just not had enough water lately, and I've been addressing
that. It's currently still in the pot that it came in, but I am
imminently going to repot it into something bigger containing a mixture
of John Innes No. 2[2] and some gravel.

Anyway, what should I do with it in the current situation? Googling
for information on leaf scorch returns lots of info on what it is and
why it occurs but not much (as far as I can see) on what should be done
about it after the fact.

Ignore it. The plant will drop its leaves in not too long anyway.
Chances are the damage is superficial - the tree sacrifices leaves first
to keep the main tree healthy in a drought.

Can I assume from this that the best course of action is to leave it
and wait for next spring? Should I do any pruning? There's at least
one branch that has 100% dead leaves, so I was tempted to remove just
that one.

The leaves may be dead but the branch is probably OK. The odd branch
might die back a bit but they change colour. It is easier to wait and
see which bits do not come into leaf (if any).

I wait until I know wood is dead before bothering to prune it - and may
take the odd crossing or unbalanced branch out to improve the shape/form
of the tree.

I am going on holiday for two weeks so it's not going to get watered
for that time, although what with the weather being what it is I'm
hoping that this won't be an issue.

[1] I've only just discovered what this is from googling. I'm no
export garderner as you can probably tell.
[2] It might be JI No 3 - I can't quite remember but whatever it is, it
is what the nice person at the garden centre recommended.

A bit of extra grit to help drainage.

Regards,
Martin Brown