Can you help to identify these frames, bikes or parts?

This frame has been in my family for a long time and has recently been re-discovered. Im looking for as much information as possible about this piece as I think its quite a rare item. Thought to be an early 1970's track frame by F.W.Evans, but I haven't been able to find any solid information on how to date this frame, or any information or even pictures of old Evans track frames.

If anyone could help I would be very grateful, and if people could also estimate how much this frame would be worth I would also be grateful.

Thanks for your help.

Hello, I'm new here.
Apologies for a double post but I found this thread after posting in and old "For Sale" thread.
Ewan, I'm pretty sure that I am the newest owner of that FW Evans Track frame.

From what I have managed to find, with some obsessive searching, is that there have been two owners in Perth, Western Australia. It's been used as both a track bike and street fixie.
I just arrived here on Tuesday 21 Jan '14; just North of Sydney and I am building it up into track bike again to race at the local velodrome (outdoor track really).
If you have any information regarding the frame's history, at least during it's time with your family? I'm very keen to have a look at it.

Cheers,

MarkT.