Hi PP
A few thoughts occur:
FWIW, I demo-ed the Leema and both the A32 and A38 Arcams
with PMC's GB1i speakers.
All 3 are great amps and the synergy all have with PMC is excellent.
To my ears the Leema shaded it most of the time but I preferred the Arcam's big open soundstage.
(I say that as someone who is not a bass head but who likes to hear what the bass is doing).
As has already been said, it would probably be a sideways move - different, but not necessarily an improvement.
But you know that!!
However, if you are willing to go second hand, and you can accommodate an extra box,
you could think about bi amping an A32 or A38 which would out perform the Leema
and this gives the Arcam's some real punch.
You can get an A32 and P35 second hand for £800 these days.
(I managed to get an A32 and a P38 for this price).
The improvements are significant because the Arcam's sound punchier and weightier bi amped.
My friend has an A38 biamped with a P35 running a pair of TB2i's.
They sound absolutely stunning.
So the other thought is what music you enjoy listening to.
Electronica, ambient stuff, acoustic guitar music, vocals, jazz etc all sound amazing with
Arcam's big soundstage and balanced neutral sound and the PMC's.
I suspect tHe issue isn't which amp to pick, it's what to do with that up-grade-itis feeling you have niggling away!!
LowFeller