Just read through that document and Wayne is as ever, correct.
Company needs to be registered to sell the plates and keep records should the DVLA or Police ask to see them.
Read it if you don't believe it.
Lukily for me i can just order the Ebay ones
All they ask over here is for the number.
Just to add, the plates ARE legal and conform to everything. However the way the company is selling them IS Illegal.