Finally got a definitive answer on this:
The rear collision avoidance component is not fitted to the V60, S60, or XC40. You *do* get the assistance for swerving around a car that pulls out in front of you, and for run-off-road mitigation.
This link explains how the system works, and implies it's fitted to all cars with Intellisafe Surround:
https://www.volvocars.com/intl/why-v...isafe-surround
However, if you keep digging, and digging, and digging through Volvo's website you eventually come across this page in the support section for the V90:
https://www.volvocars.com/uk/support...a80151706a5baa
Scroll all the way down, and you see the line "steering assistance upon risk of rear end collision". Click on the little "i" and it says "Not applicable to XC40, V60 or S60".
It's quite misleading marketing, IMHO - will be interesting to see if the dealer offers anything in compensation.