Jonathan turned up when he said he would and after listening to the symptoms and what I had been doing to cure the problem just smiled. I'm apparently not the only boat to have had this problem recently and inevitably the problem is either the injectors or the injector pump. Despite using a Baja filter, pre-filter and engine filter 'bits' find their way through and knacker the injectors and/or pump. He even had a selection of photos on his IPhone to prove it.

 Puncturing the myth of Malaysia being a cheap place to get work done, removing the pump and injectors, getting them mantled and putting them back in will come to around £250. No doubt this is why Jonathan has an IPhone. The taking out and putting back is actually a fairly minor part of the cost and of course if spare parts are needed.....