V70: Wheels/Brakes Brake Questions

[100K+]

2015MY V70 D5
Yesterday I rechecked more carefully my rear discs/pads, and found that my previous measurements were incorrect. However, during the inspection several unknowns surfaced.

1) The rear disc is held by a large torx (its bigger than the T40 which is the largest I have) Anyone know what size - VIDA only states its 35Mn torque.

2) My pads are marked 30794558 - see pic. but this part number in VIDA does not exist. 2 suitable options ( out of 6) are listed one is marked EXC (EU) the other (EU) I would have thought EU was European Union - but VIDA Abreviations suggest Exchange unit??. ( I found *558 2nd hand from an XC60 3.2AWD on the web)
However 30794555 (marked (EU) fits (according to VIDA) V70 S80 XC70 from about 2010-2015.

3) Aware that some have had issues using VIDA to rewind the Park brake I looked at the method the electrical connections to the PB motor were made.
The split point appears to be in the middle - two little tabs on the dome unclip and the sides fold back? but this dome piece will rotate clockwise and anti clockwise some 20deg both ways, even before unclipping the sides, which does not seem right. There also appears to be a separation possible at the very bottom, which I thought would be more likely, but gentle investigation with small screwdriver drew a blank.
How does this connection come apart?

Cheers

Bob.