Steve .. thanks for your response .. you too may have something there since I only buy my paprika once a year from my neighbour opposite since he makes it at home ( grows it would be better ! ) and I suppose in the course of 8-9 months it could go a bit off . I'm still thinking it's more to do with my technique though because it's only occasionally it happens and having read Chewy's response where he says to add the tom puree before the spice mix I can easily see how I may have inadvertently burnt my spice ... I try to cook on mega-heat

I'm glad I asked the question now because it's changed the order I'll add stuff so that these odd occasions become scarcer ... thanks once again