Robert Mackenzie Beverley

Probably was also the author of "The New Opinions of the Brethren ... "

No portrait or photo of R.M. Beverley?

Sadly doesn't seem to be one, either on Google or Ancestry.

An interesting account by William Kelly, involving RM Beverley:
"I was unable to attend the Conference at Liverpool in the forties, but was present at that which was held in London in 1845. Only on the afternoon of the third day did J.N.D. rise to speak, and this, after a well-known friend had alluded to his silence in singular terms. Mr. Darby explained that he had not spoken because so many brothers had a great deal to say. It was a most impressive discourse; for after many, and not leaders only, had spoken with considerable power and unction, he gave a terse summary, which set their main points in the best position, and then brought in a flood of fresh light from Scripture on the whole theme. During the same Conference a noble personage, who resented Darby's exposure of a foolish and injurious tract by himself, gave way to vehement spleen. But J.N.D. answered not a word. Another, who was no less unreasonably offended, came into the hall while Mr. R. M. Beverley was telling us what had helped him to what he regarded as the chief truth he had long wanted. The old brother (very deaf) entered, and went as near the speaker as he could, and heard him read a page of his own book, affirming the very doctrine of the Spirit's presence and working, which he himself was abandoning, and for which Mr. Darby had censured him. This incident made no small impression on me of a living God's ways."
(from "John Nelson Darby As I Knew Him")