The 3-pin plug is bound to be available somewhere. In the US we would look at McMasters catalog, but much more detailed information is necessary to identify it.There must be a business in the UK which carries a wide variety of specialty electrical items.
Good luck!
All the UL cords in the states that might fit that have a shroud on the male end ("Q" on the pdf). If it were mine I would just replace the outlets with more common ones. Assuming the innards can handle the voltage and current of your enlarger. Dead Link Removed
One oddball thing is that this might be a dedicated low voltage timer, for a 12-24v halogen lamp. They may have made it so a 'mains' line can't plug into it.
Is there a cord for the unit to plug into something?
Gary - these look like a discontinued connector type originally made by Bulgin. I think you'd be lucky to find suitable plugs now. My best suggestion would be to replace them with a modern equivalent - go to http://www.rapidonline.com and type 23-3102 in the search box for an example. Does the timer have a rating plate or anything else that might identify the maker on it?
One oddball thing is that this might be a dedicated low voltage timer, for a 12-24v halogen lamp. They may have made it so a 'mains' line can't plug into it.
I didn't know Bulgin ever made anything like that - I only know them as a connector manufacturer! As for made in GB, well the StopClock says "made in England" on it
The pins do indeed look like the same configuration as a kettle lead, but there's nowhere for the plug shroud to go - IEC sockets have a slot surrounding the pins as shown here.. Removing the plug shroud might work but there are serious safety issues with that and I strongly advise against it.