I think Seat Guru kind of went down the pan a few years ago when they were bought over by I think by Trip Advisor (please correct me if I'm wrong).
I was trying to do some research on EY when they had mixed configurations on their 77W's (3-3-3 or 3-4-3) before it all went 3-4-3.
E-mailed them at the time to ask them to amend their seating plans as they were showing duff information and got no reply and a couple of years later were still showing the old configurations.
Best one I use now is the BA Source and will advise anyone flying BA to use this.
Think Seat Guru went on a bit of a sabbatical and forgot to come back.
Happy & Safe Travels
S