Sean,
I cannot see the "cost option" on domestic energy.
Llet's look at it from an accounting point of view (which I have to often enough advising clients)
For instance, the JEC identifies domestic customers and commercial ones. It excludes domestic ones (or makes them zero rated). A one off cost to implement on their computer systems (most systems allow global changes of default VAT class to selected clients, so it is not that complicated).
Domestic fuel - again oil for central heating is easily identified by the supplier into home/commercial. They do it already internally even if not for GST.
Domestic gas - gas is again easily identified by the supplier into home/commercial.
If the import of the goods (oil/ elecrecity/gas) is treated (as it must surely be) as "approved trader status", the only charge is the one made not by customs but by the end user. If an end user is exempt (as happens with at least one business I know), no charge is made.
Cost to states of administration: none extra.
Where is the cost to the States in terms of extra people needed to manage anything?
The GST forms still get entered up by these companies, the GST remitted (albeit some less) than before. GST forms already deal with businesses which have some zero rated customers. No extra complication needed there.
Cost to states in terms of extra manpower - none.
Not much cost to the company either once in place - a one off change.
So, I'm sorry, I must be thick, but I can't see what on earth you are on about with this "cost option"?