Personally, I think masthead anchor lights are almost a complete waste of time. I recall a really scary experience of entering an anchorage in Gigha (West of Scotland) on a dark night where from a distance I was faced with a number of high masthead anchor lights. Getting closer to the boats in the anchorage, it was almost impossible to relate these high lights to the dark boat hulls at water level; indeed close up many of the lights disappeared, shielded by the top of the mast! The boats were in darkness as everyone was asleep. The only boats which we could easily distinguish were ones with a anchor/riding light set up approx 2M from deck level.
On a separate occasion, I was anchored in Bunessan on Mull (again west of scotland) which is a bay with a small pier at the head. There were around 30 other boats, most only used mast head anchor lights. During the night, a fishing boat came in at speed to land a catch at the pier, hit and badly damaged an anchored wooden boat which had only a masthead anchor light on.
I have replaced my masthead anchor light with a tricolour for night sailing. I carry a separate LED anchor light which is tied using some small rope between the genoa and the mast, around 2M off the deck, with a trailing wire back to the power socket in the cockpit. I sleep much better with this setup!
Some advice offered by marine electricians is to avoid fitting LED bulb replacements due to corrosion issues, water ingress, loose bayonet sockets etc and simply install new sealed LED light fittings, particularly for weather exposed lights.