Well less of loco more of a locomotive chassis.
Whether this is a Twinnings design sold under Bassett Lowke, who also supplied castings for it is yet to be confirmed. However signs are promising that it is indeed the 3.1/2" gauge Pacific, a smaller brother than the Colosus that was built by Bassett Lowke in 15" gauge, as a maximum loading gauge locomotive.
The frames, chassis and machined parts so far are of excellent quality. There has been a lot of work in this chassis already on the detail of it. The fully compensated front bogie is simply eye candy!
I have contacted the Bassett Lowke Society to see if they have any more information to share with me regarding the loco, also I have contacted Maxitrax who hold the Greenly Archive, they have the plans for the 3.1/2" gauge loco listed on their website. Those that don't know, Greenly was Bassett Lowkes friend and chief designer. Twinnings worked for Greenly, and always tried to encompass more details, and scaled engineering into his designs than the ordinary Bassett Lowke offerings.
Enjoy the pics, if I can answer any questions I will. Also if anyone has any more information on the loco is be very grateful for any more information.