Thank you for getting back to me.
In the scenario where you do get married abroad:
Yes you would be able to leave the UK, get married and return as long as your Tier 4 visa hasn’t expired yet. There is a small chance of you getting questioned by the Border Force at the airport because your visa would be expiring soon, however, carrying relevant documents with you to show that you intend to extend you stay in the UK would appease them.
White Rose Visas offers a service for people in that particular situation where we issue a Supportive Letter that they can carry on their person to ensure a smooth transition at the airport on the journey back to the UK.
If you chose to first switch to the Tier 2 visa within the UK around November:
Yes you would be able to leave the country, get married and return without restriction as soon as you’d received your new Tier 2 Biometric Residence Permit card. The restriction you are speaking of only applies to Entry Clearance applications where Entry clearance will only be granted with effect from up to 14 days before the job start date given on the Certificate of Sponsorship.
Please be aware that if the Home Office was to grant your Tier 2 visa to start at any time before the job start date, you wouldn’t be able to work for anyone else or study in the meantime but yes you would be permitted to travel.