Brakes dot3 to dot4 and other issues

TLDR: grinding brakes, swapping the caliper and changing to dot4 fluid

The story so far:

I changed front shocks recently along with the steering rack and clock spring. There was a bit of an issue in getting the wheel to line up and my alignment was well out, upsetting the car and going into limp mode. I had a garage fix that for me and they did but broke the volume button on the radio (presumably attempting to turn it off and turning it too far) which is why I try to avoid going to the local garages.
After changing the front brake disks and pads I got the 3 orange lights on the dash for VSC, brakes and ABS. I had seen them before when at high speed but this time they stuck around and I was able to get the codes:

C0200 front speed sensor rh circuit
C1235 foreign exchange object tip speed sensor
U0123 yaw rate sensor module lost coms
U0124 lost coms lateral acceleration sensor module

I'm having trouble with the front right wheel, the old pads were much more used than the front left. I'm also getting a grinding noise from the front right wheel like as if the pad was down to the metal.

I have removed the speed sensor and the pads given everything a good clean with brake cleaner. The disk is not damaged, everything looks ok but the grind is still there.

The lights haven't come back but I'm getting an occasional traction control light on braking even though tyres and surface are good and at lowish speeds just before coming to a full stop. The grind is more noticeable on stopping and then setting off but seems to stop at speed.

The local parts store doesn't keep dot3 in anymore so my plan is to change over to dot4 with a flush and at the same time changing the front right caliper but I'm basically just throwing parts at it. I can diy a bit but I'm not very knowledgeable hence here for advice.
Thanks

 

That's a good idea! I don't tend to use the dealer much and didn't think of them. The nearest is 20 miles away so far away in the UK but not really that far in reality