Generating invoices from OFN

Some thoughts on making sure we have the correct information on invoices when they are generated, stimulated by need to deal with this pretty soon for Enterprise User Accounts

Ideally we should be able to spec an invoice template so that it also works as a general customer invoice (i.e. for a normal order) as well as this ‘OFN Enterprise User Invoice’

Just doing a quick check, I have found this handy link for Aus tax invoices - https://www.ato.gov.au/Business/GST/Issuing-tax-invoices/ and if I get a chance before I go I will work it into a list of what fields we need to include on the invoice

@lin_d_hop have you had a look at this from UK perspective yet? @MyriamBoure @Selmo @lawrence @eric @tschumilas - I suspect it will be pretty easy to make minor adjustments to this later, but might not hurt to check if there are different fields / requirements in your countries in case we can just knock them all off at once!