VRS abs wiring

Hello folks. Been very pleased with my VRS for 18 months but now has illuminated abs warning light and tyre pressure warning. Scan reveals no signal from either rear wheel. I wrongly thought there would be a joint to a common cable somewhere at the rear or under the rear seat, it's looking like the abs signal travels up each side of the car.

Is there a joint somewhere else at the front?

I don't mean to ask any stupid questions but I have a balance issue that makes lying down to work at something really really difficult.

Thanks in advance for any advice