So being a total pedant, they are not saying you have to have HUMS at all, they (CAA) are saying that there are currently no On-Shore operators with an approval to use Vanguard. It is simply an assumption that as all Off-Shore operators have HUMS, and Off-Shore Operators can use the facility, ergo, you must need HUMS. Surely the the correct assumption is that you need an Off-Shore Operating certification to go in there, somewhat negating the utility of the site?