Question asked when ordering day to testing kit

Dhillsolihull

Does anybody know what is meant by the following question which is asked when ordering a travel Covid test?:

• “the date on which they last departed from or transited through a country or territory outside the common travel area”

All of the companies are asking the question and I have checked that this is a requirement to be compliant with the government regulations. I am just unsure whether the date they are asking for is the date I am leaving my holiday or whether it is the date that I last went outside the UK.

any ideas? 

Thank you 

onashoestring

The date you leave your holiday abroad .