Malcolm, the Search Forum facility is like the rest of the forum engine,,,,,antiquated and a pain to use.
However, when you click the Forum Search you get a box with various boxes to fill in.
In Subject just put a general term covering the interest you have,like Awnings,
Forget the Message, Username, Nickname.
In Posted Within you get a selection of dates, just choose one to start with.
In Forum, just guess where it may be
Then hit Search.
Depending on the result, change the Posted Within time and /or the Forum, or both.
Then just "hope"