Are you VAT registered? That’s a 20% difference in most sales.
I’ve never had a single issue swapping NCD between car and van – but I always use the phone to talk to someone for the best deals (direct line, tesco van,….). Its usually slightly dearer to insure a van than a similar car (unless the van has more than 3 seats which get proper expensive).
Other stuff – I’d go with Ford. Lots of options / models. Parts. Advice. Aftermarket stuff.
Maybe a Connect LWB. Or a SWB transit. Both reasonable year / miles / quality for your budget.
Tax is based on CC. My 1.8 TDCI is £200.