The KLN89B is BRNAV approved & approved for GPS approaches provided it has been installed I.A.W. the TSO.
The CAA opps department may have doubts about the approach but the technical people have no problems with it as it is EASA approved.
The KLN89 is not but there are some very good deals on KLN89B overhauled units from King that will just slide into the rack.