I can recall two occasions in the Portsmouth area when D..E.M.U. stock was used instead of E.M.U. stock, Both times in 1987, the first was in January of that year, because of snow causing problems, I remember catching in to Portsmouth a super train of a Class 33 with 2 x 4Vep/Gig coupled to a further Class 33 with 2 x 4Vep/Gig, all electric units burnt out! I was suppose to be on duty until 22:00hrs and was told to go at about 21:15, because a special was being run from Portsmouth Harbour to Waterloo via Guildford and it was likely to be the last train that evening because of the conditions. It was formed of a 3D class 207 unit. Seem to remember quite a few staff catching it, all heading in the compartments as they where lovely and warm!
The second was much later 16 October 1987 in that year and a 3H class 205 unit was used to run shuttles between Portsmouth & Havant, that being the day after the great storm!