Just taken delivery of my first RR, a new VSE Phev. Come to this out of several BMWs and disappointed to find ( I think) I need to purchase and install a micro sim to get mobile data functions working such as nav traffic, apps, hotspot, etc?? Am I missing something or if I do need a sim any suggestions on data allowance, sneaky options would be gratefully received.

For a number of years I have been buying 4G data sims from "Three".

They are 12GB of data or 12 months use, whichever runs out first. I buy about 5 a year for all our iPads and hot spots and last time I think I only paid about £24 each on Amazon. 2021 D350 Fifty Edition - Carpathian Grey
2017 4.4 SDV8 Autobiography (2021-2024) - Santorini Black
2012 4.4 TDV8 Westminster (2016-2021) - Santorini Black

You should have been given the sim card when you took delivery, my dealer supplied a 3 month one and set it all up for me.

That might be just that dealer, unless it has started more recently. Nothing like that on my Jan 18 registered car. I decided the features available through the SIM were not worth the bother for me. Only Range Rovers since 1988