is this the connector you are looking for?
Generically that is a "circular waterproof connector". Unfortunately it doesn't look like a DIN standard, once you get away from those there are many other "standards" and a lot of proprietary stuff out there. Amphenol (LTW), Woodhead/Molex, Tyco. The critical items are the number of pins, diameter of the pins, arrangement of the pins, overall diameter, and key location. If the overall diameter of the connector itself (not the nut, etc.) is 16 or 20 or 25mm then it is likely one of the M16/20/25 "standards", otherwise will take some real digging.
Since you think it is an LTW, take a look at the 5A connectors in here and see if the dimensions look similar:
If it doesn't seem to match post back, I have several catalogs in the office, can take a look tomorrow.