mk sentry

I have an old MK Sentry Consumer unit fitted with LN59xx MCBs: I want to replace the LN5905 5A MCBs with H6832s (6A, 30mA, Type A) RCBOs so that the lighting circuits are RCD protected (given that I cannot find an RCD to fit this CU). I can see that the busbar isn't compatible, so I will...