Volvo did supply them as an accessory for C70's made between 2006 and 2013. I managed to find their installation instructions on the web. The instructions were published as document number 31338928, version 1.1. The title is Installation instructions, accessories, Volvo Car Corporation Gothenburg, Sweden.
The two DRL lights are listed as part numbers 31338926 and 31338927 for the left and right side. They can be fitted in place of the fog lights quite easily and that part is definitely something a lot of owners could do.
However, the final step in the instructions is to apply a software update using VIDA and the part number for the software update is 31330690. That will require a trip to the dealer to get it done.
The DRL legislation came into force in February 2011 and my car was first registered in June 2011. There is a 2013 C70 for sale down here and that one doesn't appear to have them either. Shame really as they would have been far more useful than the pretty useless front fog lights my car has.
Having found the part numbers I have found them here:
https://www.volvoparts.tmsmotorgroup...1--16832-p.asp
The price is £250.33 so a bit expensive.
However, the best bit is the following text on the page:
** Once fitted your car will require a software download activation by your local Volvo agent, which may result in extra costs. **
I'm going to ask my local Volvo dealer how much they will charge to do the software upgrade and will report back. It probably won't be any more expensive than asking them to turn off the faux DRL's after all.