[Baffler]

But here's the thing...fom the video you can clearly see engine movement whilst turning the shaft (I assume the gearbox was in neutral at this time?) that's why I thought the inner CV was making contact with the subframe and causing the engine to lift slightly.

The only other things that come mind are the replacement control arm is too short (highly unlikely) or these replacment driveshafts are a few millimetres too long and therefore in a compressed state. Do you perhaps have the original Volvo shaft to measure from?