Partnership - BIK Rules

JayAbacus

Hope you can all support with this one please.
My client is considering forming a partnership to avoid paying BIK car tax through their legally registered business. They do have another revenue stream which they can migrate over as part of the set-up, however, they have suggested they will HP the vehicles through the limited co then recharge to their the partnership. My understanding is this will be deemed a direct link between the connected companies which would not stand up against any 'challenge' or BIK test cases.
Would it be an option for the partners to acquire direct via HP, receive business mileage direct from the limited co with no capital or running costs contributed by their legally registered business?
Furthermore, is there a need for the partnership to be VAT registered for the purpose of the HP arrangement. My thoughts being - if non vat registered - a car or van would be treated at gross level for SA taxation purposes via the special rate WDA or AIA, the revenue going through the business will be circa 50/60k per annum.