When I did the Vivaro LWB I spent £3800, the van was worth about £3k, sold it for £10300, that was last Ocober, if I'd kept it until now I probably could have got minimum £12K.
The Boxer cost £12K including vat, It should come in at a little over £6500 spent, possibly £7k with a few extras. electrics are much more sophisticated than the vivaro, much bigger leisure battery, 300ah, bigger solar panel, this all snowballs with ancilliary electrics, I'll have main electric plug in, this one has a diesel heater, fridge, the only thing it won't have is hot water which I thought about but cost and complexity stopped me. I might in the future add an awning and a pull out step so the costs may still go up.
I've insured it for £25k which is probably on the low side.