Nigel S:
The incident you refer to at Shoreham worries me for several reasons:
1) If he was not following a published instrument approach he must not go below Minimum Safe Altitude (1000 ft above the highest fixed object within 5nm of the aircraft) unless he has visual contact with the ground. (This in the ANO)
2) If he was following an instrument procedure then he must not descend below 1000ft above the ground unless he can expect the required minima in terms of visibility and/or cloudbase for the procedure. These minima are specified for each aerodrome with an instrument approach procedure. The NDB/DME procedure for 03 at Shoreham gives a Minimum Descent Altitude of 460 ft QNH / 450 ft QFE, with a minimum visibility of 1500m. Your report of breaking out at 250 ft seems therefore to be well below that. In fact it is a usual minimum for an ILS, and is well below the level of the high ground just off the upwind end of 03.
3) Unless the instructor had had the restriction lifted, he is not allowed to do 'Applied instrument instruction' which an approach with him as P1 and you as Pu/t would be. He is only allowed to teach the basic instrument flying as covered in the PPL syllabus. If he flew the approach and you logged all the time as Pu/t then I think it was illegal as he was not qualified to do that.
So in short I would be far more alarmed about this story than a quick punch into cloud around OCK. It seems that on at least two criteria you instructor was at best breaking the law and at worst risking your and his life.
Beyond that, flight in cloud is nothing to fear, but it is a good idea to have a radar service if you can.