I find lamb is the most difficult meat to curry.

I find that, in general, unless I marinate it with spices and something acidic (i.e. lemon juice) and quickly sear it before cooking the fat ends up departing a bloody awful tallowy taste into the sauce. This seems to be regardless of the cut used.

Another way I've found that works is to cook lamb on-the-bone in a pre-prepared curry sauce. The onions used in the sauce need to be well caramelised beforehand and the lamb needs to sit, refrigerated, in the sauce for a few hours before cooking. Just place the whole lot - covered - in an oven on a low heat for two to three hours. This doesn't really seem to work with lamb off-the-bone which ends up tasting like normal stewed lamb in a curry sauce.

I find the easiest option is to marinate diced lamb leg in a tikka marinade and cook ideally on a barbecue or under a high grill. Once cooked just drop it in the sauce. It will not be as tender this way, though.

The same seems to apply - to a lesser degree - to cheaper cuts of beef. I suppose this is why most keemas contain potato - I imagine the potato helps draw the fat out of the finished sauce.

I could just be doing it wrong of course.

I've always found that excessive use of chilli powder - and to a lesser extent, commercial ground cumin - can aggravate my stomach lining. Try using fresh chillies rather than ground chilli powder to add heat.

Hotter varieties of fresh chillies are available than the usual supermarket fare if you know where to look. Habaneros, Nagas and Scotch Bonnets will all add fire - and their own distinct flavours.

I'm new here and I'm wondering exactly what ROF is? I'm guessing it isn't heartburn/acid reflux...