Bauer out of Germany may be helpfull.

https://www.bauer-modelle.com/epages/Bauer_Uwe46269592.mobile/de_DE/?ObjectID=57289555&ViewAction=FacetedSearchProducts&SearchString=Lamp

Thank you all for your helpful responses. For your information this is what I found: -
Croppers - out of stock
Cornwall - Aeromat 15 x 10 lamps £10.70 for 2..
- RB lamps - out of stock
Deans - not listed on website
Mobile Marine Models - not listed on website
Model Boat Bits - non illuminated lamps in stock (but could be converted)
I have made my own navigation lights in the past but a friend without internet is wanting some , if possible, to match some on an existing boat.
My preference is to make my own navigation lights. They are not difficult to make. 😉

Flaxbybuck.
I agree re making them.
I attach a couple of pictures of Navigating lights I have made or adapted from purchased casings.The wiring aspect is simple enough.
I will get and also add a picture of a mast light I made and add on.(done)
They are easy to make.
Send me a pm if you need help.
Regards Bill

Hi
How about having a go at making your own, all you need is some brass tubing that you lights will go into, then file out a slot, solder a top onto the tube, and you now have a mast light, a lot cheaper than getting some from a retailer.
Fred

Cornwall Model Boats, Deans Marine, Mobile Marine Models should all stock masthead lights, for working lights, Component Shop have a range of LEDs...

When does one utilize which colour??

CMB link😉
😎
https://www.cornwallmodelboats.co.uk/acatalog/ship_fittings.html

Hi Try Aeronaut lighting direct or thru Cornwall model boats who from previous experience are very good and helpful.
Sorry can’t upload the link for some reason but attach a pic.
Also EBay have various items.
Regards Bill

https://www.croppersmodels.co.uk/. I have purchased from these folks and highly recommend them