Nick
To complete the picture, they also made two pre built pumps. No 12 is ideal for SIRIUS but I have never seen one for sale.
More info, courtesy of Brighton Museum below :-
PEDESTAL CENTRIFUGAL PUMPS
This is a range of pumps (Castings 'NOT supplied) for those who wish to purchase the finished article. They may be relied upon for the most arduous duty and give no trouble provided the liquid is reasonably clean.
They are used for a wonderful variety of duties. For instance: garden fountains and waterfalls, fish ponds, brine circulation in refrigerators, milk cooling, bilge pumps, water supply on yachts, cellar drainage and advertising – such as providing a constant flow of milk from a bottle.
No. 10
Similar to the No.1 centrifugal pump.
No. 12
Similar to the No.2 centrifugal pump.
Both have centre height 1˝-inches, and are supplied with Vee pulley (default) or rubber coupling for default drive.
The No.10 coupled to the smaller Stuart engines make most attractive plants. The No.12 is suitable for the "Sirius".