Replacing a Rainwater Shower head

[bricky48not]

Hello There, I'm having trouble finding a new 200mm (8inch) 'Rainwater' Shower head on a Shower Unit that was installed some 15 years ago. I've tried to find the Shower Unit 'name' from the Supplier and they seem to think it's a Yukka? that may have gone out of business now. Anyway, hopefully you can see that there is a male thread measuring 27mm on the Shower head which screws into the female swivel unit on the pipe.
All the new heads seem to have a G12 fitting. Can anyone tell me please if these (27mm male threaded) heads are still available or is there some type of adapter that has to be used with a suitable shower head that can be used for it. Much Appreciated if you can help me please

 

[muggles]

Undo this part from the shower arm and you'll find it's a standard half inch thread

 

[bricky48not]

Thank you muggles, You kindly make me aware of the solution and it just makes common sense!
The replacement Rainwater shower heads that I have looked at and will suit me, have the standard 1/2 BSP internal thread and also have a 'built in swivel joint' which is just what I want.
Many Thanks again for your information and All the Best to you!