Meriva (2011) - Code 68 intermittent fault

[Doris]

2011 Meriva - intermittent loss of power steering, all warning lights on, alarm sounding & dash displaying code 68. This happened 3 months ago.  Coolant tank was found to be leaking and was replaced. Once affected parts had dried out car was running as normal. But the same problem has just re-occurred. The new coolant tank is not leaking. Can anyone recommend an auto electrician in the North London area familiar with this particular Meriva issue