Sorry LZ, but you need to have a closer look at the picture. The bolt heads are dry.
Dip your finger in the large hole above the drip. If it's oily, then yes, the chances are that the rear crank seal is weeping.
Firstly, this isn't a massive issue as long as its a minor drip and you watch the oil level.
Secondly, what state are the breathers in, as the cam covers aren't the only seals that can fail from crankcase pressure.
Personally, if it isn't pouring out, I would be inclined to leave it be until the clutch needs changing.
It cost me a couple of hundred at an independent to swap out the seal, although if the clutch is worn, budget for the cost of the parts for that. Whilst it makes the parts more expensive, the labour is effectively free as the clutch has to come out to do the seal.
Can't see it being an MoT issue unless it's literally pouring oil out. The Omega will easily do twice that mileage if you can be bothered.