I suppose that there will be varying views/opinions about that....
... Whilst 'payment in advance' for services is common in the big wide world (utility standing charges, insurance premiums, Council Tax, Car Tax, 'memberships' etc. etc.), in the absence of 'staged payments' it is not, in general, something one usually see in relation to services provided by 'tradespeople'. Hence, if the work were split into two quotations (and two bills), one for 'the physical work' (plus materials) and the other for provision of documentation, then it would be arguably reasonable for the second of those bills to be paid after the corresponding work (provision of the paperwork) had been completed - which is essentially a formalised version of the 'compromise' approach I previously mentioned.