So long as you can show that your work complies with BS7671 & you have complied with EAWR 1989 (electricity at work regulation), the second of wich is a statutory regulation so would be the one you were taken to court over if somebody were injured or worse by any work you had undertaken, you have no worries.
EAWR description of a competent person:
- Persons to be competent to prevent danger and injury
16. No person shall be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate having regard to the nature of the work.