PS also be aware that after Brexit the UK government is likely to come hunting for a bigger contribution from expats living tax-free. It's inevitable - the money isn't there to pay for the social reforms.
With that in mind be careful how many ties to the UK you might be creating as it may invalidate your future non-resident status. Especially if the family decide to move home. I think as it stands now someone in that situation would only be allowed about 23 days in the UK per year before being classed as residential - and a layover would be interpreted as 2 of those days.
Food for thought. Challenging times ahead.