Unfortunately, this model is no longer available, but the comments may apply to other similar models.
The Revell 1:72 EH101 Merlin HAS 1 RN (04410) was only recently released and I purchased one as soon as they were available from Models2U. It was the choice of decals in the Revell version, either RNAS Culdrose or HMS Ark Royal that clinched it for me over the similar Italeri version, (plus the instructions are usually more easy to follow than the Italeri ones!)
The Merlin is one of the new generation models (not a re-release) and it was quite a surprise and pleasure when the parts fitted with an almost engineering standard of accuracy!
Of the two versions, I chose to make the HMS Ark Royal version. This involved cutting out part of a door in the starboard side of the fuselage for an extra window to be fitted. Although the position was marked on the inside of the fuselage with a thin section it wasn't particularly clear and the resultant hole was not the best it could have been. A bit of better marking would improve this.
With the missiles, I left these off until I had painted the model, mainly because they have a complicated paint plan and decals applied that the instructions don't mention until you get to the painting instructions! The colours on the instructions also seem to differ to that on the box artwork for the missiles and some homework would be advisable to check the colour scheme required to be absolutely true.
Then came the decals. WOW! One hundred and forty plus decals. More than the number of parts in the helicopter itself! The Ark Royal version consisted of grey 'tiger stripes'. These had to be applied first, followed by the general markings of the aircraft. The more dedicated modeller could opt to paint them on manually to reduce the clear borders of the decals and the problems when applying decals on top of other decals. After about three hours of decal application I needed a strong drink! Some of them were smaller than a pinhead and particularly tricky to get in just the right place, but a bit of perseverance (and having to re-glue the rear view mirrors and the missile carriers back on!) results in an excellent reproduction of the real thing. Well done Revell!