Neither the BBMF Lanc nor Dak have any 'additional' flight instrumentation added to their main instrument panels, i.e. they are both 'original'. The Dak does therefore have its twin V/UHF radios in addition to ADF, VOR/DME and ILS, the Lanc only having a VOR then TACAN mounted at the Nav's station but with no bearing readout visible to either pilot.
Both aircraft do have a modern mode-S transponder fitted.
Therefore, from an IMC piloting perspective, in addition to an altimeter, ASI and VSI, both cockpits rely on just an artificial horizon, Turn-&-Slip, Compass/DI. Not much to fly IMC safely in this day and age. That said, both aircraft are permitted to be 'flown through shallow cloud layers that do not constitute any icing risk.'; therefore flown IMC. This requirement being added to help avoid the possibility of getting trapped by an ever-deteriorating weather situation. Notwithstanding any desire not to press on into poor weather, if the 'safest' option remaining is to go up through the weather it is at least theoretically sanctioned.
The idea is to attempt to maintain wings-level flight while climbing straight ahead, not turning. Both the Lanc and the Dak have have made use of this clearance, but the debate about 'shallow layer' continued long after landing! I know of one occasion where the Lanc came out on-top with a quite considerable heading change from when it initiated the climb! With only one artificial horizon fitted there is no redundancy. The Canberra T4 was probably the last RAF aircraft where partial-panel IMC flying was taught!
Despite the warmer conditions expected in the summer display months, engine/airframe icing is the main danger of taking the Lanc or Dak IMC. Whilst the Dak does have carb heating controls, the Lanc doesn't. Neither airframe has any wing anti-ice system, the leading edge boots on the Dak having been painted on following a ground incident many moons ago.