Yes - it was just a standalone RCD which is fitted between the meter/cuttoff switch and the CU (from www.tlc-direct.co.uk) plus you have to buy a box for it.
For a pre-assembled, 6+6 Split Load Consumer Unit with 10 x Type B 6kA SP MCBs. BS EN 60439-3: 1991. 100A DP isolator, 63A 30mA RCD; 1...