It was a first defeat of the season for the hosts, who had won their first five matches but were ruthlessly put away by the excellent Londoners.
Richmond made the most of some early pressure as centre Tom Hamble threw a dummy before crossing from close range.
Tom Howlett added the extras, and his side doubled their lead at the end of the first quarter.
Suggate double extends visitors’ lead
On this occasion it was back row Aron Suggate who burst through in midfield for a score from the Rams’ 22, an easy kick following.
Things got worse for the hosts as they were unable to collect a chip ahead, Richmond’s ruthlessness in the red zone again on show as Suggate blasted over for a second.
Howlett made it three from three from the tee, but Rams got on the board with a trademark maul, hooker Harry Bicknell the beneficiary.
Yet the visitors were relentlessly physical, slick in attack, and benefitted from a plethora of handling errors which handed them possession and territory.
And they always looked a threat when entering the 22, going through phase after phase before Conrad Burne eventually made the numbers game count wide left.
Howlett slipped as he pushed his kick wide, but Richmond grabbed their fifth score with the final play of the first period.
And this time it was their set-piece which fired, Ross Sinclair dotting down before the extras made it 33-7.
Rams battle after the break
Yet Rams started the second half brightly and Bicknell again patiently used his fellow forwards to create a path to the line out wide.
With both teams ringing the changes, Rams began to gain control, then having a man advantage as Steph Hendy was sin-binned for a high tackle.
But a succession of lost line-outs in their opponents’ 22 meant they were always kept at arm’s length.
And Richmond then landed a sucker-punch with time running out, Nigerian international prop Dele Ayodele cutting a beautiful line to cruise over for a score again added to by Howlett.
The Development XV will hope to return to winning ways at Oxford University next Friday (February 13, 7.15pm).
