From The General Armoury of England, Scotland, Ireland and Wales (available on Google books):
STANLEY (Longstowe Hall, Co. Cambridge; exemplified to Sidney Wentworth, upon his assuming, by royal licence, 1856, the surname of Stanley, in lieu of Wentworth).
Quarterly, 1st and 4th, azure a saltire between two stags heads caboshed bendwise between two bendlets engrailed argent, for STANLEY.
2nd and 3rd, per chevron gules and sable a chevron nebulee between 2 leopards faces in chief and an escallop in base or, for WENTWORTH
That isn't the same as the Stanley arms you posted before?
Which is argent, on a bend azure, three stags heads caboshed or.
You could use The College of Arms to help you (
http://www.college-of-arms.gov.uk/services/identifying-a-coat-of-arms-or-crest), but they are very expensive!
I would recommend a visit to a library, to see what books they hold on Heraldry?
Unfortunately, my local library is closed until January!!
Just to add:
The Stanley arms identified above would be similar to the Scottish flag (azure a saltire argent) on which would be placed 2 stags heads (caboshed means just the head, face on, no neck visible).
The bendlets engrailed are thin diagonal lines, with a kind of scalloped edges?!
Also, Sidney had to change his name to Stanley, and not Wentworth-Stanley!