How about something different? Guessing you're starting at Duxford (?), how about North Wales and the lakes? Or maybe you could do a booze cruise to France? I just don't see the point of treading the weary path to somewhere you may well have been before. Accept you need to log about 3+ hours flying time and make the most of it.
If it was me, I would do something like Duxford - Popham - L2K. That looks pretty close to 300nm.