...But in July 1954 the company ordered a batch of 36 RVs (106 to 141), followed by a final batch of 48 machines (142 to 189) in September 1955.
Attachment 494269
The first production RV - RV 106 - was complete and tested on 5th September, 1955 - six months after the last RB was tested.
Attachment 494270
I have no information on when the last one was completed (nor whether there were any 'stragglers') but probably as few as just 84 RV buzzers were made.
I've only found photos of four RV buzzers (and only kept the tag photos, so can't offer a type study). They are:
Batch #1 (A 2868) - RV 105 - 1 machine ordered 5th April, 1954 (but never tested);
Batch #2 (A 2921) - RVs 106 to 141 - 36 machines ordered 26th July, 1954;
RV 106, test 52652, of September, 1955;
RV 116, test 52657, of 1955 - United Kingdom -
Wadkin Ltd. cast tag;
Batch #3 (A 3070) - RVs 142 to 189 - 48 machines ordered 28th September, 1955.
RV 152, test 56385, of 1957 - New Zealand -
Wadkin Ltd. cast tag;
RV 165, test 56742, of 1957 - New Zealand -
Wadkin Ltd. cast tag;
RV 177, test 57738, of 1957 - New Zealand -
Wadkin Ltd. cast tag.
Attachment 494268 Attachment 494267 Attachment 494266 Attachment 494265
And why only 84 RV buzzers?
Around 1956 Wadkin merged with or bought out Sagar-Bursgreen. They found they had then three machines of this size: the Wadkin 9" RV; the Bursgreen 9" FS-2; and a Sagar 8" model. Of course the Bursgreen merger/buy-out was in order to obtain the cheaper construction features of Bursgreen designs - and the Wadkin-Bursgreen 9" BFT soon replaced all three predecessors.