Very interesting!
Don't know anything about this one but it's not the usual configuration for an AAC strip. They usually have a single runway but the length of runway you mention is very similar. (Nesscliffe for instance has 381m and Sennybridge a slightly shorter 305m). I presume the strip can still be seen but is not in use? I'll see what I can find out but am not too confident of a positive result!
Spiney