C4 Picasso 2014: Diagnostic results for ABS/ESP/ASR plus other faults

[Byngo9]

So, My 2014 B78 5 door picasso has the following faults on dash which started when driving in the snow couple of weeks ago: ABS/ESP/ASR, handbrake, tyre pressure, anti-roll back, distance alert system. The car has had this fault before (about 2 years ago) and the independent garage took 3 days to find and fix a wiring fault on the rear drivers side ABS sensor wiring beyond the fuel tank I think they said. Not wanting to go back to the garage (weren't cheap and left my car mucky inside and damaged paint removing trims), I figured its time for some DIY.
Chinese VCI turned up and I've used Diagbox to successfully read my faults (I'm really glad that went o.k. LOL and all I have done is the global test). I wont list every fault but from what I've learnt so far on here, I've picked what I believe are most probably relevant. I'm looking for some guidance on where you experts would start to look, I think its going to be back to the same Rear Right Sensor wiring first but don't want to overlook something else considering I was driving in snow couple of weeks back when it started.
N.B the electric handbrake still works.

VIN: VF7**************[VIN obfuscated, can be read by forum staff]

1) U1213 Intersystems CAN - ABS/ESP datastream invalid
2) P0500 Intersystems CAN - Speed information wrong or absent
3) C1561 00 Electric parking brake (FSE) right hand actuator - Short circuit to positive/earth or open Circuit
4) P0562 16 ESP ECU electrical supply - Voltage too low
5) C1387 00 Speed Sensor Signals - Not characterised
6) C003A 01 Rear Right Wheel Speed Sensor - Electrical fault
a) C003A 95 Installation incorrect
b) C003A 11 Short circuit to earth
c) C003A 96 Internal fault
d) C003A 2F Signal unstable
7) U1F04-00 Engine fuse box ECU Internal fault - not characterised plus it says BSM_2010 "Important, ECU present on the vehicle but configured absent"
8) U1F79 81 Fault in the information sent by the ESP ECU - data received invalid
9) B1218 87 Absence of datastream from the ESP ECU

I do not have fault code C156C92 (picked up from another post re a techincal service bulletin courtesy of @GiveMeABreak)

What you reckon guys, start with the wiring to the rear right (drivers side) ABS sensor and calliper motor wiring ?? (my other thoughts are moisture in the ABS connector block or investigate the engine fuse box). Also unsure if those rear right sensor faults are still there because the garage didn't clear them, but found the fault went away on the dash??

Do you need the full global report? I downloaded it and obscured the VIN? (How do I attach)

[RichardW]

Given that right rear is fingered, and it came on when wet, I would def start with the wiring to that sensor.

[Byngo9]

Okey dokey. Figured as much. Just gotta pluck up the courage to tackle this cold weather now.

[Byngo9]

Since the rear d/s abs sensor (7825) wiring has been repaired before ( by garage), I'm thinking if it's that again I think I would be tempted to run a new twisted pair ( 7032 and 7031) between the sensor and connector pins 3 and 4 on ICK5D ( soldering and sleeving as close to each end as practical without de-pinning connectors. What wire type / gauge would be suitable for a twisted pair? I was thinking at first maybe a length of Cat5 network cable but the gauge on that is probably too fine.
Conscious I might have to consider the wiring to the h/brake actuator too which I think has +/- ( 7034 / 7036) and a twisted pair (7038 / 7040) but that doesn't go to the same connector under the back seats.
Finally, is it just the centre seat to remove to get to ICK5D?