The answer to your question is Yes.
MATS pt 1 Section 1 Chapter 4
"When an amendment is made to a clearance, the new clearance shall be read in full to the pilot and shall automatically cancel any previous clearance. Controllers must be aware, therefore, that if the original clearance included a restriction e.g.'cross ABC FL150 or below' then the issue of a revised clearance automatically cancels the earlier restriction unless it is reiterated with the revised clearance."
Beat me to it Speke.... I'll leave it anyway