Dear Doctor,
From time to time, you enthuse about Millers Diesel Power Ecomax as an antidote for mild emissions and performance problems. Our Rover 25 TD, with 93,000 miles on the clock, has been fed exclusively on a diet of standard Shell (not V-Power) diesel, plus a brew of Millers and Unicat 4 – an additive which has been regularly advertised in various incarnations of Diesel Car a few years ago. The car always passes the MOT test on emissions. Now, however, my supply of Unicat 4 is running out and I cannot obtain any more. Please do you happen to know where I might obtain a fresh supply, of say one to five litres?
John Hallgarth

Hmmm. Seems like you’re very much a belt and braces man John! I’m afraid that Unicat 4 seems to have disappeared about five years ago – I can find no trace of it or its supplier. There is, of course, the specialised 4WD vehicle called the Unicat, and I found a computer library catalogue named Unicat, and there’s a mythological animal that’s half unicorn and half cat – but no sign of the fuel additive anywhere, I’m afraid. I suggest that you switch to straight Millers Ecomax, which you can get in bulk five-litre containers for around £70 to £75, but watch the carriage costs. That’s really good motoring with the Rover – good maintenance pays off, as you obviously know. But maybe your published letter will unearth a reader somewhere with five-litres of unused Unicat 4 languishing in the back of the garage? We can dream, as I do every month for the Premium Bonds draw!
Doc D