The other option is to get a light bracket for the bagman that'll hold a secula, which would then allow you to move the lamp to wherever on the bike you want it depending on how you've got the luggage.
Is this a Thing or did you make it yourself? Link/illustrations? I've actually got a spare Toplight in the box of bits, so had considered something along those lines. Problem though is I detach and reattach my saddle bag quite frequently and cos it's on a Classic rack, not a Bagman, the rack comes with it – so it would need hardy connectors in the wiring and more importantly, I'd have to be careful not to put it down in such a way as to break the light.
I presume you're talking about the connectors.
Which ever connector set its a DIY as no one as far as I can tell is selling rear light looms with connectors in them (and since every bike would want them somewhere different it's unlikely to be where you need/want it.
IF I remember I'll share pictures tomorrow as I can't be bothered going outside to get them right now.
Sorry, I meant the bracket on the Bagman. I mean, it should be pretty easy to bend and drill a piece of metal to fit, but I don't have the facilities to do that, so I wondered if it was a commercially available thing. I haven't seen anything quite like that, with a curved bracket mudguard style. (At least, I think that's what I meant.. )