OP here. It's also badly wearing away the tread from the left side of each front tyre if that helps narrow it down (i.e. the driver's side tyre is wearing very fast on the inside, and the passenger's side tyre is wearing very fast on the outside). Unfortunately that makes it more pressing, else i can see it needlessly going through multiple pairs of front tyres each year, as well as being a irritant to drive
Good idea about switching the tyres around - it'll mean i get wear out of both sides of the tyre before they need replacing even if it doesn't otherwise solve or help diagnose the issue
Particularly interesting write up from sss4me, suspect i may be needing to head down that way next.
I have suspected the shocks too, but the old push-down-on-each-wing of the car test feels absolutely fine... Still worth checking, as there's not really a great deal else i can think of as i know the ball joints are OK because i specifically asked.
When i had the tracking checked, again, with the garage mechanic knowing that the pulling to the left had recurred (i'd had the tracking done at the same place not long before the pulling to the left issue came back), is it really likely he will have neglected to check the rear wheel alignment, irrespective of it being non-adjustable?
The tyres on the front are different brands, but i'm not at all sold on the idea that could cause an issue, unless i was using different sizes (i suppose the garage could've mistakenly put the wrong size on despite being told exactly what size i needed, so will check). Running tyre pressures of 32psi on the front and 30psi at the rear, not that using a very slightly different psi would cause these issues.