I'm going to beg to differ (and challenge) some of your assertions and I am going to say why... Don't take it the wrong way, the question I want to answer is, what are the authoritative references for the assertions you make.
Assertion 1 - "...any allowance must be agreed by your county council or principal authority via their remuneration committee.."
This is substantially incorrect.
Reference:
https://www.legislation.gov.uk/uksi/2003/1021/part/5/made
The Local Authorities (Members' Allowances) (England) Regulations 2003
Parish basic allowance para 25 (2):
"...must have regard, in setting the level or levels of such allowances, to the recommendations which have been made in respect of it by a parish remuneration panel in accordance with regulation 28..."
Key point - must have regard! That is not must apply. What must apply is a majority vote of the PC as is defined in:
LGA 1972 Scp 12 Pt VI para 39(i):
"...Subject to the provisions of any enactment (including any enactment in this Act) all questions coming or arising before a local authority shall be decided by a majority of the members of the authority present and voting thereon at a meeting of the authority..."
Assertion 2 - "...an allowance must be paid via the PAYE system in accordance with HMRC regulations..."
I believe this also to be substantially without foundation (unless you can reference an HMRC BIM (I've looked and can't find one) although I do acknowledge that it is widely propagated as the required procedure. What I cannot find, is the 'says who' of all this which, instead, tends to be parroted as - HMRC say so but with no reference.
Consider - Arnold Baker p164 para 16.42 which states that: "...The cost and expenses allowance are emoluments and therefore taxable: recipients must declare them to HMRC as part of their income, but may set off against them any actual expenses wholly and necessarily incurred (and not otherwise reimbursed) in the performance of the duties for which the allowance is paid..."
Key point - RECIPIENTS must declare them to HMRC - why is this interpreted as the authority must pay via PAYE / payroll? This is illogical, unjustifiable and presents a wholly unnecessary addition administrative and cost burden just to issue the allowance. When issued as PAYE this attracts employers' NI contribution and could effect the cost of Employers' compulsory insurance - since it would show that there could be many more "employees" than there actually are in reality.
I have faced this situation where the ALC advised the PC that my allowance must be paid by PAYE after provision of my NI number and UTR.
I refused and demanded a direct payment.
PC declined.
PC received a CCJ for non payment
PC paid as I had requested and in accordance with the CCJ.
It is for ME to declare the income, minus deductions, on my own SATR. I can find no authoritative reference to support the assertion that HMRC require the notification to be via PAYE as opposed to SATR.
I can't imagine why HMRC would have any interest in WHO reports the income - rather just that the income be reported.
Please do tell me / us what references or training / briefing materiel has provided the foundation for your assertions.
PS
Having checked with the Lead for Democratic Services at my own LA just yesterday, it was stated that the renumeration panel had not considered PBA since pre 2009!