Build the circuit into a replacement for a cable bulkhead socket. That way you can convert a housing that does not have room for popup flash or any optical sockets to use fibreoptics instead of cables. Does it also mimic digital TTL? Or just manual?
I'm afraid that Jean is right in this matter, my suspicion is verified, unfortunately, I have no light meter, but how do I check the strobe in this case?? I think I've got water into the electric contect a while ago, could that have any affect?? I mean that the electric contact is shielded with silicone or rubber??
Swap the left and right over. Keep everything else the same. See if the effect reverses.
I'm now thinking about travel and diving elsewhere. I think a pony is a good idea for the UK but if I go elsewhere and they don't have pony options...
When overseas, most boats on a 2-dive trip give you a cylinder for each dive. Take a buddy twinning kit and a second regulator (the baggage weight increase is only really that of a first stage, as you don't need an octopus on either). You now have twindies that you can stretch over 2 dives. You can even use a bit more gas on the deeper first dive at the expense of a bit less on the second dive.