Dear Sir,
I have, like most of us, had the same problem in the past. I have a source (in the USA) that may satisfy your requirements. (Free shipping in the USA, so I suspect that shipping to the UK should be reasonable.)
I discovered that Stanley still makes the spurs for the No. 45 (or more correctly, for the
new No. 78), and they are
essentially the same for many of the other rabbet/dado planes.
The
catch is (there is usually a catch!), they do
not fit the older planes exactly... they are made for the new Stanley No. 78 Rabbet plane, and the spurs are slightly larger. But, a few minutes of filing in a small vise and you will have very serviceable spurs! Note: the spur is hardened, so you may have to use a Dremel-type grinder on the cutting edge. The body of the spur is soft and amenable to filing smaller to fit.
They are available at:
https://www.powertoolreplacementparts.com/stanley-1-12-715-spur-kit/
I ordered four sets, as they are reasonably priced, and are far easier to modify than to build from scratch! And, far less expensive than buying vintage spurs on eBay, etc.
Additionally, like most Stanley replacement parts, they may stop making/selling them at any time! I remember a few decades past, I was able to order
many plane parts from Stanley, such as various screws, the brass adjustment wheels, knob nuts, etc.
Sadly, that ship has sailed...
Get them while they are hot!
P.S. If there is interest, I will post some before/after pics.
