Engine Numbers and V5s

[davidimurray]

Hello

In the past few days I've found a few interesting sierras from various sources. A couple of them have recon engines fitted, but talking to the owners, they never updated the numbers on the V5s. If I bought the car, had the details changed then in a years time came to register my roadster with the bits from this sierra would I have problems proving the age etc for registration purposes?

Cheers

Dave