Vodafone also don't appear to be charging extra for 5G. Their new unlimited plans include 5G coverage though the £23 and £26 unlimited plans don't really seem 5G ready with speed limits of 2Mbit and 10Mbit respectively
EE do currently look to be charging extra for 5G looking at their SIM only plans and an often significant price premium for a 5G equivalent to their 4G plans
I'd be surprised if many people were willing to pay extra for 5G especially as its only available in a handful of places whatever network you are on and there's currently only about 4 or 5 handsets which support it
