I guess am now answering my own question!
As have found this...
Parts I therefore need to find to complete what I need for the installation are:
Working from the Aerial Base down...
1 x Tab Washer - PC 47448C
1 x Variometer Adapter Washer - SD III R-140
1 x Variometer Adapter Plate - WA 623 - SD III R-113
1 x Plates, Packing No 1 - PC 76552C - ZA 2948
If anyone has any of the above parts they are happy to part with, please let me know.
Cheers
Tim