The boards are obsolete but Eaton still make the MCBs and RCBOs as spares. Will cost you an arm and a leg mind. Had exactly this couple of weeks ago.
I fitted a pair of RCBOs from another make feeding them from an adjacent MCB because they obviously wouldn't fit onto the MEM busbar.
NO doubt will get shot down for that, but it would be interesting to hear what alternative the 'cleverdicks' have up their sleeves.