Historic MOT exemption on imported vehicles

[bbg1400]

I have 2 bikes that are on C (85/86) plates. Both are imported so show their registration dates as 1992 and 1995. Both say manufactured in 1986.
When would DVLA allow them to be MOT exempt ? After Jan 1st 2026 ?
I can't find any info refering to imported vehicles on retrospective applied no plates.

[johnsmith222]

The wording on the gov website uses "built" and mentions registration seperately, so it would be worth trying. They won't be MOT and tax exempt until April 2027 though if they're using the date of 1986.

[bbg1400]

Mot exempt runs from 40th anniversary. But that's not showing. Hoping it defaults to Jan 1st. Full historic will be April 26.