I wonder why development never moved forward quickly enough in WW1, to try and attempt to mount guns on the Wings?....I mean, the SE5 had a wing mounted gun...but if Fokker hadn't cracked the Sync Gear needed..would the whole of the airwar have been fought with no forward firing Machine Gun I wonder?....I suspect, a top mounted gun (like the SE5) would have been the only alternative

One main problem must have been the load. MGs and ammo weight are heavy.
Six wing guns incl. ammo like in WW2 planes would have weighed too much.
Twin guns seemed the perfect maximum.
Now, with only max. 2 guns, and not too much ammo, you want to make sure you hit the opponent.
And the best aiming and hitting should be possible with guns on the nose, or in the prop axis.
Had Fokker not found the interrupter gear, someone else would have - maybe a British engineer.
They were all very close in developing new things, and they all had similar goals.

PS: the interrupter gear was not even invented by Fokker.
It was a German patent, but was made for a different use.
Fokker was only keen on everything he could use for his aircraft, he heard of that patent,
and he was smart enough to understand, what this device could do for him and the fighter pilots.

How's this for overkill on the guns? 2 on the fuselage and 2 on the wing.

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Actually Olham, there were both German and French patents for the system in place before 1914. Raymond Saulnier developed an interrupter gear in 1913, however the French powers-that-be saw no use for it as aeroplanes were meant for reconnaissance, not fighting. There was also the fact that Saulnier’s design relied upon the heavy and eratic firing, water-cooled Hotchkiss. If the French War Ministrey would have considered using the air-cooled Lewis instead France may well have had the first interrupter gear in use in the War.

WM, to your topic, there was also the problem of creating a wing structure in the WWI kites that would have stood up to the recoil shock of the MG's. With everything to be considered the simple solution was to mount the guns as close to the longitudinal center of the plane as possible.

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Sweet photo Jarhead. I've a hunch that kite was set up for trench strafing.

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Don't forget the Dolphin.

Standard armament was 2 Lewis and 2 Vickers mgs.
But most operated with either 2 Vickers + 1 Lewis
or just 2 Vickers.

There is a photo in Profile No 169 of a
Dolphin III with a Lewis on each lower wing, but
I think these had been beefed-up a bit.

Engine power, or rather the lack of it, was definitely a major factor when those early fighter aircraft were armed with more than two machine guns. Later in the war there were better engines available, but nevertheless the two gun setup seems to have been the optimal solution for maximizing firepower, speed and manoeuverability. It's easy to forget just how light-weight even the heaviest of WW1 fighters were compared to their WW2 counterparts. For example, a fully loaded SPAD XIII weighs something like 850 kg, easily four or five times less than a typical WW2 fighter aircraft.

SPAD XIII = full operational weight: 820 kg

Hawker Hurricane Mk. IIB = full operational weight: 3740 kg

I chose the Hurricane, because it's tail was partially wood and canvas.

Yes, that's correct and makes sense! BTW, there was case that kinda proved this which was the Sopwith Tripe which had a standard armament was One Vickers machine gun but later on some where equiped with Two Vickers machine gun but sometime after this Two machine gun armament was changed again to the previous One machine gun configuration because the weight of the extra machine gun and ammo impacted considerably on the aircraft's performance (despite adding extra firepower).

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Perhaps I've missed something here Gents, but I did not read that WM was pondering on why there weren't more guns on the WWI kites but rather why the two they had were not mounted on the wings. Am I in error on this?