Bristol Bulldog - IIA or not IIA?

 The first question I'm facing is which version to build. It seems that the IIA was the main production version (268 built according to Wikipedia), and so that's the one I'm going with. The Airfix kit also represents the IIA, which is a good start, but then there is the fact that several alterations were made to the IIA during production, and so I need to decide fairly early on which particular aircraft or at least which batch I am going to build.

The main alterations (that will affect a model at this scale) seem to have been as follows:

• Oil System: the Mk. II oil tank was mounted on the underside of the fuselage, with cooling vanes. In the Mk. IIA, it was moved to the upper side of the fuselage, and an external Vickers Potts cooler was added to the underside. The Airfix kit has cooling vanes and also the external cooler. The restored IIA at the RAF museum at Hendon has the external cooler and a plain aluminium panel, with no cooling vanes.
  
• Fuselage: circular access hatch added to the underside. This is shown in the Airfix kit.
• Tailskid: replaced with a tailwheel. The Airfix kit includes a tailskid.

Then there is the question of fuel lines. My main reference (David Luff), has a photo on page 100 showing aircraft of 41 Squadron with four fuel lines. The restored IIA at Hendon also has four fuel lines. I'm not sure if this was a feature of the Mk IIA or some special adaptation.

Anyway, here is my plan:

• Sand off cooling vanes. Add pipework to the external cooler provided with the kit (which is quite a nice moulding), and remove location lug. Drill out holes for the pipework. Fill the original location hole.
• Maybe add a bit of detail to the access hatch, by drilling out and then adding the hatch cover from plastic card.
• Decide later whether to have a tailskid or tailwheel. For instance, I could have a Bulldog from 41 Squadron, with a tailskid, or one from 32 Squadron, with a tailwheel.
• Decide later whether to have four fuel lines. I might have more information by then.

I think that's enough to be going on with. I am happy to be corrected on any of this waffle, by the way.