Simple to bell out when you've got that cpc just sitting there. Just stick a bared brown end into the screwhole of the box and bell from the other end to find...
Saying that, I prefer working with brown/blue rather than brown/brown.... but then I haven't seen any of that since it was red/red.
So, following on from everyones suggestions.… my van contains brown 6241Y, blue 6241Y in 1.0mm and 1.5mm..... 6242Y in 1.0, 1.5, 2.5, 4.0, 6 and 10... G/Y singles in 10 and 16 along with 25mm tails...
1.0, 1.5 and 2.5 singles for working with conduit.... in brown, blue, black, grey and g/y…….
All that, and a cable roller... (black and decker workmate and a broom handle) in the back of my little van....
I've had to leave all my tools at home!
Seriously though. I've just started using 1.0mm more than 1.5 for lighting. A bit easier for terminating into downlights with push in connectors. Find 1.0 is easy to snap in a screw connection