G’day all and Pete, I have had a look at my brass whistles and these are some more accurate observations:

Ex-Herb Gimbert Whistle: Lacquered Brass, Lead Fipple, Generation, Key D (actual pitch is ~20 cents flat of Eb), 283mm x 12.85mm. Label is a red decal, now almost totally obliterated. Pitch is not stamped, so I presume it was included in the decal, as in modern Generation whistles.The use of a decal does not necessarily indicate a modern date, as decals had such a vogue in 1862/4 that my Shorter Oxford Dictionary lists the word Decalomania ... although it does not list Decal.

Ex-Sally Sloane Whistle: Lacquered Brass, Alberts, Key F (actual pitch is ~10 cents flat of F#), 236mm x 12.0mm. Label is a soldered-on brass band, 6.5mm wide at the back, bearing an oval 31.5mm high and ~25mm wide with the words: THE BOOMERANG FLUTE above a boomerang and below: ALBERT’S SYSTEM. There is no country of origin marked, but construction and decoration (narrow turned bands on the brass barrel) are quite similar to the Generation whistle.

The pitch (F) is stamped into the barrel directly below the label with a precisely positioned, nicely made, serif-style letter.

The third whistle of this type is currently on loan to the Music Museum at Kurnell, so I cannot check its exact details. My Flute database shows it as being stamped D and doesn't mention other markings. (Maybe I imagined the stamped brand!)

The question of the persistence of this pattern really depends upon where you look for examples. During the late 1970s or early 1980s, I bought several brass whistles, presumably made in India, constructed of light brass tube ... fabricated by soldering a seam in what appears to be rolled up brass shim.

These are all branded with a brass band in the shape of an oval; approximately 13mm high and 45mm wide with joining tabs. This is marked KUMAR FLUTE with one word above and one below the larger word MADHURBANS - contained in a rectangular border. This may or may not be the same as the town Madhurbani to the north-east of Patna. They are decorated with the same style of narrow turned bands around parts of the barrel as the older whistles.

The fipple on these whistles is made of more brass shim - shaped into an open sided box (with a cut-away for the curve of the mouthpiece) and soldered into the squared-off whistle end of the instrument. I would have to suspect that they are probably not soldered together with lead-free, food-vessel solder!

All these whistles are about 20 cents flat of the semitone above their marked pitches of low G and A so that they are almost in Ab and Bb. When I needed a whistle in A for a radio programme some years back, I carefully cut an A whistle about 50mm below the whistle end and lengthened the tube (by about 15mm) with a fabricated tube (about 73mm long) of brass shim, with a carefully formed, stepped overlap. The whole affair was neatly assembled with epoxy resin. This was surprisingly successful, but I find my Susarto in A rather more accurate ... if a little uncooperative at times.

This persistence of this particular design reminds me that, in the 1960s I bought some Hohner Whistles (in the keys of low G, Bb and C) of similar design, except that these were made of heavier, factory-extruded brass tube, and were nickel or chrome-plated. These also had the fipple constructed of a complicated box form and, sadly, never delivered a really good sound ... and were between 25 and 40 cents sharp of concert pitch. I have not seen these instruments advertised by Hohner in recent decades.