The only document that matters is The Guide To Judicial Independence which states
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| Quote: 3.10 Sufficient reasons for not sitting on a case include: (i) personal friendship with, or personal animosity towards, a party; friendship is to be distinguished from acquaintance, which may or may not be a sufficient reason depending upon its nature and extent; (ii) current or recent business association with a party; this includes the Justice’s own solicitor, accountant, doctor, dentist or other professional adviser; it does not normally include the Justice’s insurance company, bank or a local authority to which he or she pays council tax. | |
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It doesn't mention any future contact, although it probably does mean that judge won't be able to sit on any case involving Samsung for a couple of years after he finishes working for them.
However it does also say
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| Quote: Propriety, and the appearance of propriety, are essential to the performance of all of the activities of the judge. | |
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You could certainly question 'the appearance of propriety' given the period between the two events is quite short.
It would of course be best if sitting judges were required to take no external work while sitting but given the amount of money they would be passing up to do so - any lawyer who has made judge would be able to commend very high fees indeed - would mean the only judges we'd get would be retired old duffers. Oh no, hold on...