Why Are Some UK Postboxes Gold?

I've skipped 'N' and 'O'. Although I intended to skip 'N' anyway, my video for 'O' just didn't come together and so I decided to move straight on rather than dwell / upload a bad video. I think at the end of the series I'll have an epilogue episode about the 4 letters I missed (F, I, N & O). 'A Great British Adventure' is a series of videos that have taken me all over the UK. The videos are based on the new A-Z 10p coins - they aren't videos about the coins, rather, they use them as a sort of contents page. They will be uploaded every 3 days for the next 3 months or so, although there will be some miscellaneous videos in between. Instagram: @halfasleepchris