Actually the vehicles in both photos at the above URLs are clearly identified
on the caption as class 101 DMUs which have been refurbished. These units were
a proprietary design by Metropolitan-Cammell and, while originally built during
the same time period, starting in the 1950s, as Mk 1 coaching stock, were _not_
Mk I designs nor even based on Mk I.
Most first generation DMUs were proprietary designs of their builders though
some lower seating density units used for cross country or intercity use were
more closely related to Mk I.
There was quite an extensive refurbishment programme undertaken on DMUs around
1977 when these units were around 20 years old and selected ones were regarded
as having a similar life ahead of them. It was decided to paint the refurbished
units in this off-white livery with a rail blue band on the side, presumably as
a publicity measure to promote this refurbishment progress to the public.
Previously these units, being regarded as "non-main line" stock had been in all
blue livery. I am not aware of any low seating density DMUs with Mk I features
which were refurbished and painted in blue/white, the only DMUs I know of being
high density ones which definitely had no relationship to MkI coaching stock.
Unfortunately, like many another livery with large areas of white paint, the
"Refurbished DMU" livery tended to show up any dirt only too well and was
fairly quickly abandoned in favour of standard rail blue/grey.
EMUs for the Southern Region _were_ Mk1 stock but that is a different matter
altogether and obviously would not even be eligible for "Refurbished DMU"
I am not aware of any coaches other than these refurbished DMUs painted in
Blue/White livery, apart, of course, from the "Blue Pullmans".
Alex. W, Stirrat