Don't own the bike anymore so it's not longer a problem but yes, it was a combination of running big tyres, trying to get even clearance around the tyre and having to space the guard away from the mount at the chainstay/bbshell so it didn't rest against the seat tube
Is it not possible to set the wheel near the lips of the drop out so it'll be easier to drop the wheel vertically?
Or is the tyres too big to allow it to sit near the lips?