I have the opposite problem too wide a gap between the case and fixed bars.
Anyway, not U.K., but I’ve had three, two for fixed bars, nicely made straps from HANDDN in Vietnam via Etsy.
Not cheap in comparison to a Hirsch Toronto. I would say the leather around the bars is quite thin, perhaps too thin for my watches however acceptable for nicely made straps.
Good range of leathers and colours, well made with neat stitching.
Unfortunately, on holiday until the middle of the month.
Another good strap maker, based on one strap purchased, on Etsy is JonesinTokyo. Even more expensive.
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