Bofors gun maker ID?

[Darkman]

A friend here in Australia acquired this sad remnant of a 1941 dated Bofors from the turntable up. It's missing a lot of parts, but does have the breech casing and mounting data plates. The breech casing plate maker is "RD" and the mounting "AR". I would assume it's British made, so could anyone tell me who these makers are?
Someone on another forum suggested it may be a Royal Ordnance Engineering Factory, but none seem to match the RD (or AR) monogram?


Thanks, Graeme

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