Mystery Leak on Left Hand Side

My previous post on this subject was lost in the revamp, but I'd come to agree with other posters that it had to be the gearbox. The theory was reenforced by my last crawl under the car seeing what appeared to be a tiny weep from the bottom of the nearside seal.

With an 800+ mile round trip to Scotland starting today I was back under the car last night with the idea of pumping the spare half litre of gearbox oil that I had into the box. However on removing the filler bolt there was an immediate steady stream of oil running out, indicating that the box was healthily full.....

So, 3 months and 500+ miles of regular 50p size oil stains doesn't amount to as much as I'd feared if it is the box. The car is off to Retro Sportscars later in July for it's new rear suspension arm, so perhaps they will find/solve the leak.

 

Given that the oil should be level with the filler plug hole, maybe the gearbox has been over filled with oil and the leak is a result of that