In the manual it shows a USB connection in the front arm rest box for certain options. Does anyone know if there is a UK option that gives this and has anyone retrofitted one? Seems a much more sensible place to have one.

Over here it comes in a pack with 2 rear USB plugs, armrest USB and rear 220V socket. 

We don't get the 220v socket in the rear in the UK as the European 2 round pin socket doesn't meet UK standards and they don't substitute it with our three square pin socket.  I don't know why they can't fit the rear USB sockets though.

The rear USBs would be useful for the kids as well although they have a 12V socket back there so easy to plug in an adaptor that gives at least 2 USB ports. Would still like something in the arm rest as would make charging the phone etc much neater.

I´ve ordered the option to get the "in armrest" USB socket for my Carstick. A fully working retrofit seems hard to do; it involves a "datahub" to distribute the signals. If you only want the charging function, I´m sure you can fit an aftermarket charger in the armrest wired to the rear seat 12V socket.

my car has got also 220v rear socket, but i haven't use it jet

about built in USB sockets can't say any good word,

the provided power isn't enough to able feed now days 2A devices

 

i use these in front and rear 12v sockets

https://www.aliexpress.com/item/QC3-0-Quick-Car-Charger-Qualcomm-3-0-3-Port-USB-Car-Charger-For-Nexus-5X/32804609097.html

 

but once have got problems with start engine two weeks ago have ordered new, with voltage display

https://www.aliexpress.com/item/SOONHUA-Car-Charger-Dual-Port-Type-C-5V-3A-QC3-0-Mobile-Phone-Charger-Quick-Car/32843200786.html

 

Both new iPhones, iPads and galaxy S7 will happily charge from the rear USB sockets, no fastcharging but to keep them alive it works lika a charm

 

230V Socket in the rear is quite good but the form factor is a problem as most laptop chargers won't fit.