Spouse-ILR–Absences During the 2 Year Probationary Period

[manci]

According to Immigration Directorate Instructions, Chapter 8, paragraph 4.6:

There is no specific requirement in the Rules that the entire probationary period must be spent in the United Kingdom... Each case must be judged on its merits, taking into account reasons for travel, length of absences and whether the applicant and sponsor travelled and lived together during the time spent outside the United Kingdom. These factors will need to be considered against the requirements of the Rules.

Is there any specific guidance, or precedents, on the allowable absences of the spouse (with a spouse visa) of a settled person, when applying for ILR at the end of the 2 year probationary period? In particular, with regard to: - the lengths of the individual absences, the aggregate of all absences, the purpose of the absences, whether the absences were with or without the settled spouse, etc.?