Painting exterior woodwork

[Humpy D]

Am embarking on a refresh of the exterior woodwork but need a bit of advise before I start.

The existed woodwork is pretty sound - no flaking or rotten wood - so I was simply going to rub down, give 2 coats of undercoat and finish with 1 top coat.

I was going to use a Crown paint which I used for some interior doors earlier this year (as it says it's suitable for interior and exterior woodwork) but I'm not wondering if I should use a specialist exterior paint such as Weathershield.

I suspect the answer will be 'Yes' expecially if I don't want to do the job again in a year or 2 but should the undercoat be an exterior one too or will the Crown interior/exterior undercoat be ok followed by Weathshield?

Thanks.