Should I re-number the series?

So, here’s the thing… so far there are six books in the main Anna Burgin series, but one – In The Frame – is a series prequel novella.

The original plan was to call it book 0 as it predated the series chronologically. (In The Frame is set in 1989 whereas the others start in 1993.) But Amazon wouldn’t let me call it book 0, so I made it book 3 instead, as I wrote it after Out Of The Red.

Now, however, I wonder if that was an error. In The Frame can be read in any order (although it makes most sense if you’ve already read one of the others.) But the direct sequel to Out Of The Red is Fade To Silence.

I’m thinking of doing a box set of the first three books in the series, but the first three full novels would be Cold Press, Out Of The Red and Fade To Silence – ie currently numbers 1, 2 and 4.

So… should I re-number the series and make Fade To Silence book 3? Or just leave it as it is? Let me know your thoughts below… any feedback is very much appreciated!