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I'm starting to research my family tree and have managed to get hold of his RAF record (he was a rigger in the last months of the first world war) - Having a little trouble working out where he was actually posted and also his level of participation in the war. I have attached his posting record.

Any help appreciated specifically with the below but any other advice appreciated:
•   RO I suspect is recruitment office - Is there a list of recruitment offices anywhere?
•   I suspect he then was going to 86 FS (Flying Squadron) but this changed to 30 FDS? (18/07/1918) where he remained until 12/06/19. Anyone know what 30 FDS was?
•    Then there are references to 1 Concen Group / 1 Con Group between 12th and 14th June 1919 (It would appear to be some form of transfer) – anyone know the correct decipherment of the terms?
•   he then ended up in Rein Park/ Rein Depot which I believe is a reinforcement depot near St Omer from which he was discharged toward the end of 1919

Thanks both - I was specifically looking for what the abbreviations might mean:
RO I suspect is recruitment office - Is there a list of recruitment offices anywhere - I suspect he then was going to 86 FS (Flying Squadron) but this changed to 30 FDS? (18/07/1918) where he remained until 12/06/19 - then what is 1 Concen Group / 1 Con Group between 12th and 14th June 1919 (It would appear to be some form of transfer) as he then ended up in Rein Park/ Rein Depot (which I have now learnt is a reinforcement depot)

So any details on where I might find recruitment office details or what the 1 Concen Group/ 1 Con Group reference might refer to would be appreciated.