Of my five, three have had to be returned to Bremont for attention due to losing time.
My Solo was regulated once under warranty but had to go back again for the same thing out of warranty. Bremont regulated it again and, generously, did not charge me. However, it's once again losing time and will need attention for a third time.
My S500 was losing time and the date wheel did not always operate properly. Returned under warranty and all has been good. It's now sub 2s a day.
My Broadsword was losing over 45s a day and has just come back from regulation but it will need to go back again due to positional variation. It is slow by 5 or 6s a day on its side, but loses up to 23s a day lying on it's back.
Neither of my Valjoux based watches have had an issue, only the 3 handers.
I don't know what the issue is but I agree with the OP that there do appear to be many more reports of Bremonts requiring warranty repairs, which is unfortunate since part of the draw for me is the fact they are chronometers and, presumably, that's one of the reasons for the price point.
I must say that the customer service experience has always been impeccable but it does get tiresome being without a watch while it makes the trip back to Henley on Thames. It's also difficult when people to whom you have personally recommended the brand take the plunge and experience issues, sometimes necessitating repeat trips back to Bremont before the situation is rectified.
So, that's 3 returns, all 2824 or similar movements. There does appear to be a pattern.