1) You now DO need a number plate for an mot (introduced about a year ago).
2) The only bikes exempt from having a headlight are those first registered before 1930something, or bikes where the primary use is off-road endurance, a 999r with nobblies doesn't count!
A daytime mot will let you get tax and insurance, but won't let you ride on the public highway. No exceptions other than those listed in 2)