https://assets.publishing.service.gov.u ... 2.0ext.pdf
@secret Simon,
in the above link section
Continuation of lawful leave during absences from the UK and then
On or after 24 November 2016
The continuous period is maintained if the applicant either:
• leaves the UK with valid leave, applies for entry clearance before their leave
expires, is granted and re-enters the UK using that entry clearance
• applies for new entry clearance within 14 days of their leave expiry date, one of
the circumstances below applies, their application is granted and they re-enter
the UK using that entry clearance
Also in the following section:
Breaks of leave and allowable absences
For any acceptable breaks of leave, the period spent outside of the UK will count
towards the 180 days allowable absence. This includes any time:
• while their leave remains valid
• after the expiry of their leave
• while the entry clearance application was under consideration
• before they entered the UK once entry clearance had been granted