reynoldsno1,
I agree from overhead the beacon the procedures are predicated at a max speed of 240kts, for a catC aircraft, according to Pans-Ops 8168,Vol 1, but most countries, the UK included, have a differences to Pans-Ops writen in the AIP. ie: max speed 185kts.
(see also ICAO Pans-Ops, 8168 Vol 2).