I also favour Red-lored, given that there is red present between the bill and eye. Gilbert's Whistler does not have red in this area in any plumages, with the red being limited to below the eye and bill.
Ok gentlemen, i'll take that as a consensus and if any more serious, hard core, experienced bird nerds wanna throw their two bobs worth in; then we stand corrected :) Incidentally, that's why on most years I go back to round hill/nombinnee area around Sept which is when the RLW are more likely to be active/seen....even Gilbert's are an absolute thrill for me, their calls (similar to RLW) are far reaching and enigmatic, one of the highlights in my birding 'career' :)