Thanks for your questions
If any time this property abroad was your main residence, then PPR is given for the time that you lived there and up to last 3 years of ownership (under the PPR rules)
No you cannot elect a property abroad as your PPR, as whereas with a property in the UK (that is NOT rented out) its possible for you to actual spend considerable time in it (along with another owned property or when you rent elsewhere)
But yours isn't even in the same country.
As you are bot domicile, if you do NOT bring the sale proceeds into the UK, then you may be able to ask for this gain to be disregarded for UK tax purposes, but this will result in a loss of personal allowances for the year, and depending when this property is sold if you have been in the UK for 7 out of the last 9 years) you will also incur a remittance basis charge.
And if the money is in brought into the UK, then it will form a liability here under the normal rules of UK taxation.
But I must stress as its been more than 2 years since you bought the property in question, so its too late to elect anything as a main residence so your ability to nominate has ceased.
See here from the HMRC capital gains manual as what can be nominated for information purposes
There are extensions for the private residence relief on property which has been the main residence and now no longer is, due to employer providing accommodation etc, but again on the basis of the information provided these do not fall within the criteria of what you advise.
And I will also add the time limit for the two year election starts from the time a change of residence position changes.
You advise that you use this house for a few weeks each year, but this is not where you conduct most of your life, and from what you advise have never lived there on a any full time basis, so the property would not qualify anyway.