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@Scilly.Suffolk
What are the cranks? Do you still have the original BB?
The standard chainline for a road double is around 42mm/43mm, measured to the spider arm between the rings.
Assuming you want to keep the ring on the outside for aesthetic reasons, then you will need a BB a couple of mm smaller than was standard, depending on the chainline at the rear.
If you don't have the original BB and you can't find out what size it was, then you could use any BB, measure the chainline and work back from there.
What sort of rear wheel is it? A proper track wheel, a road wheel for a screw-on freewheel or a road wheel with a freehub for a cassette?
If it is either of the first two, then the only way to tune the chainline at the rear, is to swap the spacers around to move the hub; as a result you may have to re-dish the wheel to re-centre the rim to account for the offset hub.
If you have a freehub, then you can use spacers to move the sprocket around on the hub and avoid re-dishing.
Bearing in mind your line of work, I wondered if you might have access to a cheap/free respray, in which case you have no excuse for not giving it a rad fadez job!