Before I did anything else, I'd rotate the desk 90 degrees clockwise so it was firing down
the long axis of the room.
As for that kit, I wouldn't buy any foam wedges. I
don't think they'll give you very good bang for your buck (or indeed scarcely any
measurable effect at all) in reducing your bass mode problems. With your budget, I'd spend
100 pounds on foam tiles and the other 100 pounds on some rigid rockwool to knock together
my own bass traps.
I'd put most of those foam tiles at the left, right, and
ceiling mirror points.
Now for the oddness of the room: With your desk in its
new position, all that glass in the back might just let out some bass energy and help
solve some bass unevenness problems. (It sure isn't helping so close to your left ear at
With your desk in its new position, you'll likely have a bit of an
echo coming back at you from the 60cm bit of wall behind your right shoulder. So, at a
minimum, I'd deploy a bit more foam tile there at head height. Alternatively, that corner
(as well as the two front left and right corners) would make a good place for a
floor-to-ceiling 45-degree bass trap made out of rockwool.
As for that little
1m square bit in the lower LH corner, I'd try hanging a duvet in front of it to damp down
the HF reflections in there, running the remaining width of the duvet over the glass
window (the one that would be behind your head with the desk in the new position).
Do you need a machine room? That little corner looks like it might make a great
place to stash a noisy computer, if you could get some long enough keyboard/mouse/monitor
cables or some wireless solution.
You could also get more serious about bass
trapping back there but I'm not 100% sure how I'd approach that. Here's hoping someone
more knowledgeable than I comes along...
hope this helps a bit!