I believe you are confusing Lewis guns with Vickers KO Guns. Both used a pan magazine but the Vickers ROF was in the area of 1,000rpm. the SAS had them as the guns were obsoleted when the RAF went to power turrets with .303 Colt Brownings, Stripped of the Cooling casing and radiator the Lewis could be mistaken during a quick glanceThanks, I'll see if I can find a copy.
I think the larger gun on the foredeck is one of these, equipped with an autoloader.
Britain Vickers 3-pdr (1.4 kg) [1.85"/50 (47 mm)] QF Marks I and II - NavWeaps - looks late Edwardian
MisterBoatMagazine guy seemed a little dismissive of the side-mounted twin Lewis guns.....but they were a notoriously accurate weapon ashore, which is why the SAS jeeps mounted them.
View attachment 466765
(I suspect in the AA role their primary purpose was to boost the crew's morale)
The boat which has been refurbished is one of the 'short' type.....later MTB's ( so designated regardless of their role ) were 115 feet overall.
Hazy memory tells me that some of the later MGB/MTBs were equipped with Quad MG mounts aft (?).
( this may be a Hollywood induced hallucination. )