Thanks for the range of helpful comments and suggestions.
@Mike-And-Jane0 Thanks for the suggestion which seems to be the best course of action for now. I suspect if we refuse to pay cash when we arrive, then we will be told we can't stay and left in the middle of nowhere on a Sunday night. So it makes sense so cough up whatever is requested and take it up with AirBnB.
@Ricardo85 Thanks for the extract from the TORs. This is in line with how I expected it to work and how it has worked for me in the past - charges for cleaning etc. clearly itemized.
@Ian-And-Anne-Marie0 and others - I understand that listings vary greatly, but I don't understand why you wouldn't just include an itemized cleaning fee in the price breakdown when that is clearly possible to do.
I can also see you might have to pay for bed linen on a campsite, but - in a fully furnished house - I'd think it would be better to make it very prominent in the listing that this is an extra - rather than putting it in nearly 7000 words of terms and conditions under the "show more" section of house rules.
As for the consumables, I am assuming this will be a charge to use water and electricity - but who knows how much? Or what else might be included.
Above all, it being asked to pay cash on site that seems distinctly dodgy to me.
Maybe this is unfair, but I will be very reluctant to book a property that is marketed through an agent or company in future. Our experience of individual hosts has been universally excellent.