Have you worked out an answer to this yet?

Not yet - I am waiting for the car and will then consider the possibilities in conjunction witht the dealer. (that could be Feb/March).

However, the only significant remaining question is whether to use a dual system with the front and rear cameras swapped.

Crikey....is it that long a wait for the xc40?

Volvo XC 40 Dashcam
 

I’ve been using one of these since January and I’ve not noticed any problems. Positioned right up high, about an inch from the top of the radar on the passenger side . https://www.amazon.co.uk/gp/aw/d/B06...L0BBLHLX&psc=1

FitcamX
 

This seems to be a popular option where people seem to fit them quite easily. The only issue I can gather is it does not indicate gps and road speed. I am still debating whether to fit on in my 21 XC40 -

https://www.amazon.co.uk/FITCAMX-Sui.../dp/B09C3394KV

I have a version from a well known chinese fast site that is the same as this(they buy them there then resell them) but much cheaper, have had no problems at all in 9 months, mine shows speed and you can see versions with gps.
Take about 3 minutes to install the front one and very tidy, mine is a 23 full electric