Overseas trips after obtaining BRP

Hi,

Could you answer what I think is a simple question.

After picking up a BRP card from the Post Office in the UK, how frequently can you travel outside the country during the first 30 months and is there a limit on the duration of one trip or trip durations over one year?
The reason I ask is that we live in Thailand and have to collect the BRP card this month but the plan is to return to Thailand immediately after for 2/3 months to sort out various business as well as me continuing employment in which I shall resign in late November.
The ECO for some reason put a start date of 5 October for the vignette despite clearly putting a planned arrival in the UK on the application form of 8 November.

Thanks.

You are free to travel.

No limit on absence.

You could have the visa vignette corrected if it is UKVI error.