I would say any water that has large perch would do... are you a member of any clubs...? Billericay, Chelmsford, Ongar all local clubs with waters with good perch in them... there is the Rivers Lea, Roding, Chelmer, Can, Wid, Ter, Blackwater... so there is plenty to go at... a lot of commercials won't allow drop-shotting and I would venture that the perch fishing doesn't really start to get productive till September time...
I'd recommend joining a club and trying their waters
I also have had limited success with drop shotting and have had more fish with lightweight jigs...
Have a look here for some enlightening and entertaining info...
journal 2015
The venues these chaps fish are not local (midlands I think) but they seem to have some good results with small jigs and their methods are bringing them some success