Brentwood: this woodland is one of the best places to photograph roe and fallow deer.

THE COPPICE
Wooded valley. Forage blackcurrants in July around the wetter parts. 
Find bridleway off School Rd, Kelvedon Hatch, Brentwood, CM15 0DH, almost opposite junction with Mill Lane. BW leads through The Coppice into Pole's Wood. Keep walking 4 miles for Chipping Ongar via Great Myles FP and St Peter's Way.
51.675386, 0.272277
10 mins  

THORNDON, JURY HILL
Collection of hornbeam and oak woodland peppered with ponds, dells and commons.  
Find North Car Park, off The Avenue, Warley, Brentwood CM13 3RZ. Walk back W towards the gatehouse and turn left (S) into the bridleway just before the gatehouse that runs at the bottom of it garden. Keep following the BWs south all the to Jury Hill, past Childerditch Pond.
51.583343, 0.339609
20 mins

WEALD PARK, THE FOREST
Best place in S Essex to see fallow deer. Fawns are born in June. Listen for rutting roe deer during July and August.
Find car park on Weald Road, Brentwood CM14 5QJ. Walk north and east towards The Forest, Deer Park and streams that run into lake.
51.629852, 0.271836
10 mins