Short answer is- I don't know, but started another thread recently about my 10yr old ceramic crown crumbling away.
My NHS dentist said another ceramic one would be £660- but wouldn't recommend it because they don't last as long, as shown by my old one!
There was another option for £750 and a zirconia (think that was the name) was £880. There was no mention of an NHS priced crown and at the time, I was just getting the prices to know ahead of time IF I wanted to replace the metal in my current one. I 'assume' those prices are to get it privately at my NHS dentist.
Edited to say that all the above are tooth coloured on the outside.
Sorry I can't help, but a hopeful bump anyway.