I bought my Heljan 17 from D&F models in Glasgow in July. I saw it on the shelf and asked David, the proprieter, how they were running. He took his glasses off, looked at me intently for a couple of minutes then asked "what have you heard?"
To cut a long story short he explained the problems they have encountered then showed me an example that they had altered themselves. 5 minutes later, after a lengthy test, I paid ??79 and walked out with a (D&F modified) example and have never regretted it, it runs excellently. David also said when the replacement chassis arrive he would replace it with a new one if I was dissatisfied. I'm not, but have spent a lot of money with D&F models since then, not only because I'm a great believer in supporting local businesses, but because I'm just a completely satisfied customer. I'm eagerly awaiting the second batch and will buy another example from D&F, I wouldn't be that keen on buying an example on mail order however!