"British Military Test and Evaluation Aircraft: The Golden Years 1945-1975" by Malcolm V. Lowe is filled with experimental and one-off Meteors.
Some of them are:
EE227/G: originally featuring a cut down tail, later tested out RB.50 Trents (The "G" in the registration number stands for "Guard", meaning an armed guard was always present when this aircraft was on the ground)
EE348: radar testbed
RA490: flew with MetroVick Beryls, later converted to Nene powerplants.
RA435: used to test the Derwent 5s, fitted with afterburners
EE397: used in aerial refuelling trials, later set an endurance record of 12 hours using this system
WD604: testbed for jettisonable wingtip tanks, found to be better than jettisoning underwing tanks, never adopted
VZ442: canopy jettison testbed, flew without canopy
WA982: testbed for Red Hawk, Pink Hawk and Blue Jay
WK935: prone pilot testbed
VW443: drone testbed
WD790: radar and weapons testbed
WD765/5: used at the ETPS
WM373: weapons testbed
Hope that this might help.