I'm trying to download GBPCBS1Y= via APII need filed for Mid price
R Studio is not an LSEG supported product. There is a community version of library for R, and you can see the usage example in the GitHub page for the library.
You might use some code like -
ex2 <- rd_GetData(RDObject = RD, rics = "GBPCBS1Y=", Eikonformulas = "MID_1")
