Thanks. The costs do matter - because the principal authority charges us £1500 per election (unless there is more than one election occurring at the time) - for a parish that only has 350 houses (with a precept of £9000, which on a per-head basis, is average for the region).
The principal authority has doubled their charges in the last few years, and smaller councils are really annoyed by that.
I will approach the principal authority for a breakdown of their election charges, but they have been coy about break-downs (which might reveal costs associated with postal votes).