I don't know to what extent the infrastructure itself has changed - but given National Grid themselves don't think it'll be a big issue, the grid itself is probably still capable of that 62GW (even if generating capacity is less).
I haven't mentioned CO2 in my comments because that was not part of the original discussion. "Its not even clear how we are supposed to produce the necessary amounts of electricity" is patently false in the case of the UK. Maybe overall CO2 production would be less, maybe more - that's a different (though important) discussion. At least with electric vehicles there's a clear technological roadmap to 0 emissions - there's no credible roadmap for 0 emissions with internal combustion engines.
Vans aren't likely to be vastly different from cars - eg the Ducato Electric claims 235 km on a 47 kWh battery - vs a Model 3's claimed 265 km on a 50 kWh battery. HGVs are much heavier vehicles though - the path for electrification for those is likely to be slower.