Is the query that
a) repairs are not part of the check price (that would be very unlikely to be the case).
or - and I think this is the issue -
b) they are just not able to fix anything even if you did pay them? and so you have to go elsewhere?
Problem with situation b) is that you are maybe getting told you have a problem you already knew (gas burner say) and then you go elsewhere and end up paying someone else to diagnose the same fault and then pay them to fix it.
I see these Habitation Checks in the same kind of light as getting an AA/RAC check on a car - Handy if you are buying so you can negotiate with the seller to get fixed (or money off), but on a vehicle you already own is there any real point?
I think if it was already my van, at the least I would go to a 'one-stop shop' who could deal with the basics like fixing a hob or fan or whatever.