The Warships and Westerns had preheaters, I don't know if other types such as English Electric did. The WR hydraulics did seem to be free of the huge smoke clouds (and sometimes flames) that you seem to get from these other types on cold starting. The noise you can hear from inside an otherwise shut down Hydraulic is the preheater. Bear in mind that hydraulic diesels were physically smaller but ran twice as fast to give the same power.
The USA/Canada had a different approach, and didn't shut down, the diesel would be run for weeks, often well away from base where they were just left to thrum away overnight. Part of this was the coolant systems on US diesels were long prone, until recent times, to have coolant leaks, to the extent that it was not cost effective to use anti-freeze, so they used plain water, topped up daily (sometimes more), and much of their territory has temperatures way under freezing in winter. Idling fuel was cheaper than anti-freeze in the quantities leaked. If the loco does have to be shut down there's quite an elaborate water drainage procedure to be done (it's the first thing that base does going out to a derailed and overturned loco in winter, drain the coolant water to avoid it freezing and ruining the engine block). The old longstanding GM 567 engine from the 1940s-60s, supposedly unburstable, was particularly prone to this, and the inside of the engine room, despite drain holes, is commonly awash, with of course a film of lubricating oil on top making footsteps inside treacherous.
It's very difficult in such a large piece of metal with great temperature differentials between shut down and running to keep everything fluid tight, which is why these issues arise. A further startup problem is lubricating oil which has leaked down past the piston rings into the cylinders as things cool down, this can be the cause of some of the extreme smoke on starting, as it is burned off in the cylinders. Broadly, black smoke for lube, grey smoke for unburned fuel.
Same approach in Russia, where also the city bus garages (and military bases apparently) don't shut down the engines in winter, go past them overnight and 100 buses are rumbling away to themselves out in the open. Part of why they've always liked trolleybuses and trams more, no engine starting problems with them in winter (ice on the wires is a separate discussion).
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