DEANB:
Killingbeck Atkinsons.

This photo is one of a series of photos taken by the late Mike Deuchars of Edinburgh, arch Atkinson enthusiast and hugely knowledgeable in the subject.
Depicting the letter A, the 7 motors shown are John Killingbeck’s six 38T Atkinson 6x4 tractors, with the 32T 6x2 unit in the middle.
I know you’re expecting some detail so…

Front left, STC 262M, started life as a rigid-6 flat with Chapman Envelopes of Darwen & Balham, and has been modelled by Corgi - incorrectly as a big 75T unit 
Front right, LCK 480N, started life with Pandoro at Fleetwood, working permanently with a Tasker low-loader:
LCK 480N Atkinson Venturer T4566C by Chris Gardner, on Flickr
After being re-powered with a Gardner 8LXB in lieu of the original ■■■■■■■ 290, and also a spell as one of John’s “Mk.3” Atkinsons with a 400 Seres cab, it was sold for preservation as an engine-less chassis cab, and has been rebuilt with a different cab and a different big ■■■■■■■■
LCK 480N 1975 Atkinson Venturer by wheelsnwings2007/Mike, on Flickr
Curiously, the original cab with its Riding sleeper conversion, and which lay on a trailer in Killingbeck’s yard for several years, was sold separately for preservation and is now on an Atkinson Defender!
LCK 480N Atkinson Venturer T4566C by Gardner 8LXB, on Flickr
Dave Lawrence Atkinson Defender by Dave Stretton, on Flickr
In the middle is MVD 432L, named by Mike Deuchars as an Atkinson ‘Buccaneer’, is now in preservation in North Yorkshire. Paul has documented it’s history here…
wjriding.webs.com/regnomvd432l.htm
(Paul Gee also caught it in its original 4x2 form whilst still with Ridings, many pages up on this astonishing thread)
No.30, second on the left hand side, is GCY 802N, originally a Defender 8-legger, and which went on to a life beyond Killingbeck (most unusual in those days, as most of the wagons were “recycled”) with John Jardine of Wishaw:
Atkinson Ventuerer, GCY 802N, John Jardine. by Chris Pattison, on Flickr
No.31, second on the right hand side, had quite a career! Like STC 262M, it started as a 6x4 flat with Chapman Envelopes:
Colin Woodburn on the move by Harry Robert Teague, on Flickr
It then became John’s very first 38T Atkinson conversion:
VTD 495M - No.31 by Mike Slater, on Flickr
It was then rebuilt with a Riding sleeper conversion and finally became the first of John Killingbeck’s ‘Mk.3’ conversions:
Atkinson Ventuerer, VTD 495M, Killingbeck Transport. by Chris Pattison, on Flickr
Fed up yet?
The other two are RAO 207M at the back left, and MWR 726P at the back right.
RAO started life as a 6x4 rigid with Edenhall Concrete of Penrith, and was rebuilt by John as a 38T tractor:
Atkinson Searcher RAO 207M by Chris Gardner, on Flickr
Like GCY 802N, it went onto a commercial life beyond Killingbeck:
RAO 207M Atkinson Searcher by Chris Gardner, on Flickr
before finally retiring into the capable hands of John Ramm:
John Ramm - RAO 207M @ Gaydon 11-06-17 by ROBERT MATTHEWS, on Flickr
Which just leaves MWR 726P, about which I know very little
In fact, I don’t even know if it was a factory-built Venturer or a conversion:
Atkinson Venturer MWR 726P by Chris Gardner, on Flickr
It did become another ‘Mk.3’, and it’s in the background of this photo of VTD 495M:
Atkinson Searcher VTD 495M by Chris Gardner, on Flickr