Okay, so upgrade time. I had to keep my acceleration and jerk quite low to avoid ringing (500mm/s^2 and 5mm/s), so I ended up getting linear rails for both X and Y axis. 3x 500mm MGN12H Hiwin rails ended up being slightly over £100, but they’re worth every cent as I currently use 15 jerk and 2000mm/s^2 with pretty much no ringing visible. I also upgraded to 9mm belt instead of 6mm, as the belt I originally had was quite low quality, so I was going to upgrade it as well and the price difference between 6 and 9mm is small.
The extruder still has the same specs as before, I just redesigned it to use less horizontal space to allow for a larger effective work area.