The mid-'60s also the contraction of the Southern Region's activities in the far south west of England, resulting in the WR gaining a much higher route mileage with a territory now stretching from Penzance to Salisbury. This western expansion caused the use of 116 units on long distance services for which they were considered unsuitable, due to their lack of toilet facilities, to remedy this situation seven Laira hybrid sets were assembled at Newton Abbott, this involved the substitution of the Class 116 DMS cars with those of Swindon built Class 120 units. The latter of course being equipped with toilets in both the DMS(L) and the TS(L) vehicles. This operation resulted in both the 116 and 120 sets being equipped with one toilet in each type of 3-car set treated, long distance passengers travelling in what was essentially a 116 set needed to make sure they rode in the appropriate vehicle as at that time there were no gangway connections fitted to class 116 vehicles. They were now mainly based at Exeter, and worked on some of the longer ex-SR lines such as Exeter to Padstow, Bude, Ilfracome and Plymouth via Okenhampton as well as the former GWR routes to Kingswear, Paignton, Torquay and Plymouth.
When these sets were disbanded all but two of the original DMS cars were returned to their correct sets, the two incorrectly paired remained that way until their eventual withdrawal in the late 1980s.
The swaps were:
*51141 (from LA 303) was exchanged with 51590. However, as LA 303 had a lavatory (it was power cars 51128/41 with Class 118 59481) 51590 changed with 50921 in LA 311.
In the early 1990s Tyseley put together about 25 hybrid sets formed of a Class 116 DMBS and a Class 101 DMC for use in the Midlands. They were given set numbers in the T031 - T056 range.
One of the oddest combinations occured at Tyseley during 1976 when M50835 and M59334 were paired with Class 100 DMBS M50343 in place of Class 116 DMS M50888. One CF based 3-car unit W50090 W59040 W50132 was disbanded in 1970 and the two power cars were used as single units numbered (set 101) and (set 102). These vehicles were used as extra power units in support of the Swindon Cross Country sets, being attached at Cardiff for services to Shrewsbury, the 116s would normally be locked out of use as were class 121 units which performed the same work. The set was later reformed using TC W59344 and was transferred to the ScR in the mid 70's becoming set 116385, this becoming the only complete 3-car unit of the (4 lamp fronted) first batch to work in Scotland.