It's only the C1, D1 entitlement Ron, not HGV etc. Anyone who passed their test way back when, got C1, D1 automatically. More recent licences do not include C1, D1.
C1, D1 allows the holder to drive minibuses up to 16 seats and medium size goods vehicles (3,500 - 7,500 Kg [3.5 to 7.5 tons]).
Without C1, D1 you can still drive anything below 3.5 tons (which includes Luton head Transits etc) and minibuses with up to 8 seats for your own use and as a 'volunteer' (for club outings etc).
If you choose to keep C1, D1 then you do need a special medical form filled in by a doctor and/or optician. This will obviously entail some cost.
As long as you have the C1, D1 entitlement you can hire 7.5 tonners with ease.
When I was going to do the house move myself, a 7.5 tonner was the obvious choice and all the local hire firms had them available at reasonable cost but they were in high demand from small companies and bigger couriers.
This sums up the situation nicely...
https://www.vanrental.co.uk/vanblog/archives/5083