Just found that Ring do a 120% brighter than standard bulb, lasting 400-500 hours (about 1.5-1.7 years for me, commuting every day and a bit more on sat and sun).
Also Philips do a 100% brighter than standard blue tint bulb which, whilst losing out on overall brightness is still stupidly bright whilst having a slightly different colour that will a) stand out better when filtering and might make people look twice given it's a blue light. Based on the Philips Xtreme Vision (or Power, I get them confused), the bulb should last the same as the Ring at 400-500 hours.
Both are road legal and are on amazon at decent prices.
I'm also looking at an LED set up to mount below my standard bulb for extra visibility. Just can't decide which one to get, big or small.
Also for extra visibility you can probably get away with mounting the white version of this on the front of the bike or if you wear a hivis vest you could run it around that to make yourself a christmas tree.