Dry pulley bearing

its a 1999 td5 defender, i have what sounds like a dry bearing on the pulley directly above the crank pulley ( i assume its the cam pulley).
Mot man said it was possible it was a noisy water pump bearing but with the belt of i can feel and hear roughness in the cam pulley, so figured id change that first, as its easier,
problem is- i can't find anyone who stocks the pulley, does anyone have one for sale or knows the where abouts of one

the one directly above is the viscous fan drive.err5285 is bearing ,cam is inside the rocker cover driven by a chain

thats the one james, i knew the cam was chain driven but thought it was the best way to descibe its location as i have taken my fan off as they keep puncturing radiators when offroading and a stone gets between blades and rear of rad, thanks for the info though

wow there pricey rascals are'nt they, £55 +vat for a bearing