You are missing 17 of 629 known Acorn 8-bit ROMs ROMS

ADFS v2.10 (1986)(Acorn)
BASIC48 (1986)(Acorn)
DFS NET - 1119E (19xx)(Roff)
DFS v2.20 (1986)(ACP)[a3]
Electron Expansion v1.00 - Plus 1 (1984)(Acorn)
Electron Expansion v1.00 - Plus 1 (1984)(Acorn)[a]
Electron OS (19xx)(Acorn)
EPIC v2.47 (19xx)(C. Manning)
Everest (1986)(M. de Weger)
Master v1.00 (1985)(Chalice)
OS Electron (1983)(Acorn)
OS v3.2 (19xx)(Acorn)
OS v5.1 (19xx)(Acorn)
PRES ADFS - E00 Library (1987)(-)
PRES ADFS v3.31 - E00 (1983)(Acorn)
Watford Electronics DFS v1.44 (1986)(A.C. Bray)[a]
ZDFS v0.90 - E00DFS (19xx)(-)[b]