Thats a very interesting lot, I wonder if it sold?
Although it appears to be a standrad RAF Full Dress tunic, I have to say for several reasons I dont like it. To begin with, the rank on the sleeve is not an Air Officer, but Flight Lieutenant. However the shoulders have epaullettes with rank too, and what appears to be (by the description) the rank of Squadron Leader, the next rank up. Around the button on the epaulette is a bullion wreath, which is normally seen on rank epaulettes of officers with Air Rank. So effectively we have three indications of rank here.
The full dress tunic did not carry epaulettes. There is a bullion oakleaf cluster on the collar, which did feature on the full dress. However, the pattern is incorrect for the RAF as is the bullion trim. The material, going by the photo seems too light in colour. The rear has two buttons which would be correct for Full dress.
The belt is interesting. As mentioned before, buckle looks a little like the RNAS Full Dress version, although we cant see if the eagle faces left or right.
I think it is one of three things. It is clearly based on an RAF Full Dress tunic, but has so many oddities, clearly isnt one. It may be a prototype, although if the name is genuine I doubt it. It could be a very early RAF Full Dress (circa 1918 - 19) when the force went through several changes of uniform, derived from the RNAS/RFC amalgamation. Or its possibly a film prop, based on an RAF full dress. With the two lots of rank, both different, I'm inclined to think the latter.