Manchester HON/LISTO SIDs have additional speed restrictions, although some airlines regularly 'forget' to follow them...
Non jets and small jets 240-250kt IAS up to FL260
All other jets 250kt max up to FL100, then 280-290kt IAS to FL260
In this case, 'no speed restriction' would cancel the speed profile and the pilot can fly as fast (or slow) as they like.