score:2
Having been motivated by this question to do more research, I perused the OED for per centum and related entries. There it is made clear that the use of the (pseudo-Latin legalese) phrase per centum (or it's abbreviation per cent) is meant to be translated literally, as per hundred.
Therefore the phrase inquired upon, £10 per cent, should be read as £10 per hundred [pounds].
Upvote:4
To me it simply looks like it is meant to say "10 pounds sterling per 100".
"cent" is short for the Latin word for hundred, "centum", and £ is the symbol for "pounds sterling".