The opening poster has not stated under what conditions a Labour party Government has come to power in those early days of November. It could well be that it has formed a coalition with the Scottish National Party at Westminster, which for me would be the most likely outcome should Labour not hold and an overall majority.
It could also be that Britain has "crashed out" of the European Union with no deal while Parliament was prorogued for the election campaign.
In the above situation, I would imagine that the new coalition or a majority Labour government would immediately request the European Union to grant Britain temporary associate member status on the same terms as the United Kingdom holds now while new negotiations are held as to the future relationship of Britain with the EU.
Should the above request be granted by the EU (and there would be no reason for the EU not to grant such a request) then the Negotiations could follow the same path as the Labour Party policy as recently laid out.
That policy is, to hold fresh negotiations on Britons withdraw from the EU, and whatever the outcome of those negotiations that would be placed in front of the United Kingdom electorate for acceptance for leaving on those terms, or an alternative given of remaining within the EU on the present terms.
Should it be that a majority in England, Wales and Northern Ireland elect to leave the EU, but Scotland elects to remain, then powers could be granted the Scottish Parliament to hold a fresh referendum on cessation from the United Kingdom to enable that nation to remain in the European Union.
