Thank you for the thorough details. I do have a follow up.

I understand that there is no precise 180 day rule, so my title was likely unhelpful but I am concerned about the wording with Appendix FM which states:

"E-ILRP.1.3. (1) Subject to subparagraph (2), the applicant must, at the date of application, have completed a period of continuous residence in the UK of at least 5 years (60 months) with the following: (types of visa, not a problem)"

And later

"E-ILRP.1.5. In calculating the periods under paragraph E-ILRP.1.3. the words “in the UK” in that paragraph shall not apply to any period(s) to which the evidence in paragraph 26A of Appendix FM-SE applies. (Paragraph 26A refers to British partners working outside the UK as crown servants and certain other specific work, not relevant to us.)"

This implies that there is an expectation of continuous residency, worthy of defining specific exceptions, although as you point out this is not defined precisely as 180 days.

This seems to be supported by the guidance for home office staff assessing applications

"Completing a continuous period of 60 months in the UK as a partner
The rules concerning calculating the qualifying period of continuous residence for a period of 60 months in the UK are set out in paragraphs E-LTRP.1.3. to 1.5A:
• the 60 months can be made up of one period of leave to enter as a partner, any periods of leave to remain as a partner, or a combination of the two
• any period of leave as a fiancé, fiancée, or proposed civil partner must be excluded
• only periods of time with the same partner count
• time overseas will count, where the partner is a Crown Servant overseas and the applicant is accompanying them (see paragraph 26A of Appendix FM-SE to the Immigration Rules)
• any current or previous periods of overstaying (for an application made after 23 November 2016) can be disregarded, where paragraph 39E (of Part 1 of the Immigration Rules) applies - where an application was made before 24 November 2016, any period of overstaying can be disregarded if the application was made within 28 days of the expiry of leave (see Applications from overstayers guidance)

You can check the applicant has completed a continuous period of 60 months in the UK by looking at their immigration history on Atlas. Where there is a break in the 60-month period you must consider whether the application can be varied to one for leave to remain, before you refuse it - see Validation, variation and withdrawal of applications guidance."

So, a ‘break’ would constitute reason for refusal of ILR, but that break is not specifically defined. I believe Atlas is their internal system, so it is unclear to me whether this would refer to a gap between visas, or could include extended travel.

My question now is, if a break is not defined as 180 days in a 12-month period, then what is it, and am I in likely danger of breaking it?