Further to my #673 I have now consulted Wiki which gives the following:
The flotillas wore combinations of bands on their after funnel to identify them. From 1925 the following bands were worn;
- 1st Destroyer Flotilla — one black band
- 2nd Destroyer Flotilla — two black bands (one red from 1935)
- 3rd Destroyer Flotilla — three black bands
- 4th Destroyer Flotilla — no bands
- 5th Destroyer Flotilla — one white band
- 6th Destroyer Flotilla — two white bands
- 8th Destroyer Flotilla (from 1935) — one black and one white band