(I’ve been practising my google search skills.)
Kenjo’s suggestion is good. That is the most likely place for the Creda Solarplus model label. But apparently it often falls off.
The reason that you need the exact Creda Solarplus model number is that whilst the controls and elements stay the same for years the cosmetics such as doors, handles, control knobs and fascias can change many times over the course of 15 or 20 years. The exact model number is the only way to identify the correct replacement for certain.
If you cannot locate the model number on the oven then perhaps your operational manual gives a clue?
Or you could look at pictures of creda hinges to see if you recognise one and are prepared to risk ordering the wrong one.
One place to try and spot your creda hinge is http://www.buyspares.co.uk/search.pl?query=Creda+Cooker+%26+Oven+Door+hinge&t=95122.9559945354
Neil s, November 2013