Trolls and misinformation agents will try to reduce BoEVAT to an argument about VAT or take you off at a tangent to the point in question. Either they just don't get it or they are being deliberately misleading. Either way it is the genuine justice seekers who will suffer.
I have read a lot of responses that focus too much on Value Added Tax and whether or not the PCN issuing company have to account for it.
This is a complete red herring because it is not about them accounting for VAT, it is about you accounting for VAT. You need it on record for your own VAT accounting purposes. They have to include VAT on the invoice; even if they are so-called zero-rated. They must account for VAT even if they charge it at 0%.
Where a company is not VAT registered or is exempt, this must be clearly stated on the invoice.