But just under a spousal visa you are not considered leave to remain- you have to apply for that AFTER the spousal visa period...
Is that not right?
No, any visa that is issued in the UK is called 'leave to remain'. That includes a spousal visa issued in the UK (FLR(M) - Further Leave to Remain, based on Marriage), or a student visa or a work visa issued in the UK.
There are different types of 'leave to remain'.
ILR is
indefinite leave to remain, while a spousal visa issued in the UK is
limited leave to remain.
The discussion here is whether or not spousal visas issued outside the UK meet the requirement, because they are limited leave to
enter, not to remain (as 'remain' means you have to already be living in the UK when the visa is granted).
However, they have the same restrictions/rights as FLR(M) (they are basically the same visa), so I think it's just the wording on the driving website that is confusing.