On my fg conversion, I had to attach the chain ring to the inside of the crank - where the smaller chain ring would've been when it was a road bike - to get a straight chain line.

I've just bought a new chain ring - when I attach it, do I need to flip it so that the marks (which would face away from the frame) will now be facing the frame? This would mean the chain drop pin is toward the crank. I haven't got the bike with me atm so I'm trying to picture this as I type.

Hope this makes a lick of sense...
Cheers.

It partly depends on the ring. If it's one made for single speed, meaning it has no cut down teeth for shift gates, then it doesn't matter which way it faces. I'd remove the anti-jam pin and flip it so the counterbores for the chainring bolts are on the right side.

OTOH- if it's a derailleur ring with the cut down shift gates, these don't work well backward so I'd leave it outside out so it's turning in the normal direction.

Yup, it's a 105 derailleur ring. So you're saying i can put it where the small ring would go, but have it facing out (as it would if it were in the outside position)?

Yes, move it over, but don't flip it.

Note that this means that there won't be a counterbore for the chainring bolts, but that's no big deal 99% of the time. (you need enough clearance to the chainstay, but that's very normal)

Excellent, thanks for the tips. Much appreciated.