Contract and Purchase Department

[Resmoroh]

Hello All,
Can anybody tell me what the Contract And Purchase Department was and did in WW2?
They seem to have been a department of the Admiralty? They appear at RAF Lagens, Azores, in 1942 and I just wondered if they were some subterfuge method of putting apparent “civilians” into a neutral country in war-time?
I am investigating a nurse (Norah Emma Williams, a UK SRN?) who is at Lagens in 1940 (from FWR) with a number 103086. In what series is this number? 103086 comes up on the LG a number of times – but not for this individual. She comes up a couple of times in the LG with 5501. That’s her PMRAFNS Officer number – but her Commissioning into that service is not in the LG – possibly not published in the LG at the time for fear of “blowing the gaff” on the subterfuge?
I am getting out of my depth here!! Can somebody explain, in simple terms, what was going on? I have asked the PMRAFNS Association the same question but – as yet – no reply!
TIA
Peter Davies