There were 5 Angus & Greener design registrations preceding RD 209161.
Jenny Thompson (page 14) gives them as:
RD 117501 of 21 December 1858 - Parcel 6 (Dish)
RD 197703 of 24 May 1866 - Parcel 1 (Bottom of decanter)
RD 197704 of 24 May 1866 - Parcel 1 (Decanter)
RD 200233 of 25 August 1866 -Parcel 6 (Dish or butter float)
RD 205812 of 26 January 1867 -Parcel 4 (Decanter and stopper)
She also shows the design representation for RD 197704.
I haven't seen examples of RD 200233 or 205812, and they are not illustrated in Thompson.
See below for photos of RD 117501, and the following post for RDs 197703 & 197704.
Fred.