As I recall there were only two when I saw them so it must have been Calshot.

I knew I knew something about it, but obviously not enough. 🙂

No problem with carburettors, IIRC on a merlin it’s at the back of the engine. Turn the engine over (not quite that simple) and leave the carb the right way up. Gipsy Twelve AKA Gipsy King was inverted and carburetted.

Streamling also no difference. Visually, saw the nose off a Spifire and a ‘109 and turn them over and that’s it. Compare the Bf109 and Buchon as one example and the DB-engined Spit as another.

Upside down or the right way up makes no difference to fitting a cannon as it still fires through the V.

I believe it’s just to do with vision over the nose. However it brings in other problems. The thrust line changes, which is probably easy for an aircraft designer to sort out, and with a geared engine by bringing the prop centre nearer the ground it will need a longer undercarriage, or smaller prop.
As already stated, the Merlin was planned to be inverted but it was dropped after resistance from the aircraft manufacturers.
As well as the DB range, it didn’t seem to cause any problems on 20-odd thousand Gipsys, including a V12.

I appreciate this is painfully obvious, but as Gloster built virtually all Typhoons, what happened to their drawings?

I also am reliably informed I’m a Grumpy Old Man, so I’m now working at it.

I haven’t seen the book but did see the TV series. The strange thing is that it’s Mrs DHFan that told me I’m a GOM, and she also agreed with virtually everything said. 🙂

My MkII had the Moss box, in fact it had two as the first one fell to bits. You get used to them. Shows how long ago it was, second-hand box, with overdrive, already removed from the car at a Jag specialist breakers – 14 quid!