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The general consensus amongst experts on this site is that you should be in occupation for at least a year to avoid assessment.
As for the chalet upon which you paid CGT, which was almost certainly correct as it was not your sole or main domestic residence, you should have received Lettings Relief (LR) up to 40K to offset any gain for CGT purposes. However if as a holiday letting property it was available for letting for over 210 days in the year and actually let for over 195 the situation becomes incredibly complicated bringing Entrepreneur's Relief into play to reduce the rate of CGT to 10%.
I do hope LR was claimed at the time. If LR was not claimed then there is another CGT can of worms to be opened and argued through a suspicious HMRC!
Perhaps you are beginning to see just what a horrible tax CGT can be, likely to spring up and bite you in a most expensive way at the most unexpected moments.