I just fitted bosch,£7,50 each from Andrew Paige Factors, also got a set of leak off pipes £5,OO. Not sure of your location .they are in the North West, mine now starts bang on the button. hope this helps.
you can get beru plugs from german swedish,for about 55 quid.
Island 4x4 have Beru at £8.50 and "Glow Heater Plug P38 2.5TD STC3103" for £3.69
Anybody know if the cheap ones are any good?
I would recommend that you do not fit cheap' ones.
My garage did and they feel apart in the engine. The ceramic casings broke up.
Ceramics and Piston rings don't mix well.
I would only fit Bosch or Beru (Beru are original equipment) from a reputable supplier, another £30 is far cheaper than an engine rebuild after scoring your liners and breaking a ring or two!