Does anyone know the specification of the gauze used as a fuel filter at the inlet of the rapid preheater (part #187) and the main burner foot valve (part #195) please? Part 187 is described as Sieb (Sieve in English) Mine have become blocked and attempts to clean them resulted in disintegration. I have some fine brass gauze but it is about twice as coarse as the original. I'm aware that base camp sell replacement #187 and #195 so may go that route if the gauze cannot be found.