As a previous agency recruiter and then owner, and having contracted with Blue Panorama, I can speak with some inside knowledge.
Firstly, as a rule of thumb, all an agency looks for is a bona fida and honored contract that keeps both themselves and the contract personnel happy, they want to get paid as well as the contractors want to be paid but that is living in a perfect world.
Not just Blue Panorama but I have contracted with a number of Italian Airlines and, pretty much, they are all the same, well it seems Italian accountants are all the same, whereas they pay no attention to invoice "pay by" dates whilst Flight Operations may well be cancelling flights because contract personnel have downed tools having not been paid.
Of the Italian Flight Operations Management I have worked with, G.T. of Blue Panorama in particular, all they want is a happy workforce with services operated and often themselves they are "shouting" at their accounts department to pay the invoices with only so much effect, Italian accountants really are a law unto themselves.
Yes, the agencies do hold a one month security deposit which is to be used as a last resort, if that were used to pay the personnel one month or monthly then any security deposit is gone and as soon as the Italian accountants may learn that staff are being paid before the invoices are paid then they would delay paying the invoices even further.
But, from the airline perspective, some contract personnel are their own worst enemy and tend to give contract personnel in general a less than good reputation and, of course, such word spreads to accounts departments thus may influence them to delay paying contract personnel invoices.
And without knowing the precise circumstances of "English Rendezvous's" complaint I have previously experienced contractors and their creative accounting including one First Officer who went ballistic because the airline refused his claim for 24 hours per-diem for being away from base over 31 June and, if not picked up before invoicing, will delay the payment of such invoices.
I'm out of the industry now so I have no personal interest to distort the truth, I'm just saying how it is, or was, and the problem was, is, and shall always be, the Italian accountants.