Time Electronics are well-known in metrology circles, and are still going strong after nearly 50 years. Based down in Kent:
http://www.timeelectronics.com/
I've got a small number of their products. In fact, I've recently done an article about the 1030 Micro Cal:
http://www.markhennessy.co.uk/time_e...1030_microcal/ - I was really impressed with how helpful they were when it came to restoring one of mine.
That one is a combined voltage or current source, and can supply up to 100mA from a PP3 with no problem - just not for very long
I also have a 404S, which is very similar to your 505, but a voltage source rather than a current source.
These sorts of things are incredibly useful to have around if you're doing R&D. Some people use them to check the calibration of their meters - a bit like those Chinese voltage references that we've been discussing in recent months - but to use them for just that is a waste of their capabilities.
If you're not sure what you'll use yours for, I'll give you £6 for it
