Just the usual Adam; Les Myxomycetes, The Myxomycetes of Britain and Ireland (Ing) and Myxomycetes – a Handbook of Slime Moulds (Stephenson and Stempen).
Dave
I think that counts.. lol, I’ll put that down as a definite Ceratiomyxa fruticulosa var fruticosa then 
FRDBI has
Ceratiomyxa fruticulosa (O.F. Müll.) T. Macbr. 1899 (=Ceratiomyxa fruticulosa var. fruticulosa)
Ceratiomyxa fruticulosa var. arbuscula (Berk. & Broome) Nann.-Bremek. 1975
Ceratiomyxa fruticulosa var. flexuosa (Lister) G. Lister 1911 (=Ceratiomyxa fruticulosa var. fruticulosa)
Ceratiomyxa fruticulosa var. fruticulosa (O.F. Müll.) T. Macbr. 1899
Ceratiomyxa fruticulosa var. porioides (Alb. & Schwein.) Lister 1911 (=Ceratiomyxa porioides)
Ceratiomyxa mucida (Pers.) J. Schröt. 1889 (=Ceratiomyxa fruticulosa var. fruticulosa)
Ceratiomyxa mucida var. flexuosa Lister 1894 (=Ceratiomyxa fruticulosa var. fruticulosa)
Ceratiomyxa porioides (Alb. & Schwein.) J. Schröt. 1889
Ceratiomyxa sphaerosperma Boedijn 1927