S80: Wheels/Brakes strange occurance - electrical?

[fordlover]

XC70 D4 2015 , 46,000 miles. MOT due in 4 weeks.
40,000 mile service c/o @ 41,675 miles. 11 months ago.

long trek home yesterday from working away, 110 miles. all was going well, then after a brief stop at the late shop just 1.5 miles from home the car started acting up. first i got ECS error message, then ABS error message then the very serious looking BRAKE ! (red triangle) warning. then within about 200 yards of home the car seemed to 'stall' very briefly, then it kind of slowed as if in limp mode. i was down to about 20 miles of fuel so i initially thought it was a fuel probelm. i pulled to the kerb and gave it a little revving in park. seemed fine. so with just 200 yds to go i carried on. it got worse. anything above walking pace was accompanied by a very aggressive 'rattling/clattering' noise from somewhere around the front nearside wheel. immediately taking my foot off the accelerator the noise went away. all the warning lights on the dash were still on, now accompanied by the Tyre Pressure Level system light. I managed to coax the car car home and onto the drive. it was very late so i left it until this morning.
I popped the bonnet, couldn't see any sign of leaks or low fluids. underneath i fully expected to see something horrendous like a drive-shaft hanging off. nope, nothing. started her up, no warning lights. gingerly backed her off the drive, no issues. a little more bravely took her around the block, still nothing. ventured as far as the petrol station. no issues, gave her some diesel and returned home with no issues or warnings whatsoever.
I am thoroughy confused and worried. what could it be? what caused it? must be someting wrong somewhere. the rattling/chattering was quite visicous.