Really, only chillies and peppers and their relations cause the burning sensations so almost all other spices should be fine. A short list might include cumin, cardamom, coriander, tumeric, fenugreek, star anise, cassia bark , fennel seed. ginger, galangal, caraway, mace, nutmeg, cloves, saffron and tamarind. In almost all recipes the 'hot' content can be scaled back (and probably should be, Brits especially are suckers for 'macho' cuisine).
Go easy on the chilli powder/cayenne pepper. Only add as litle as you thinkyou would like. You can get mild chilli powder which would be OK for a start. After a while you may like it stronger. I always say I don't like hot currys but my friends think mine is hot. A slow start is the secret. All the other spices are fine with the possible exception of ginger, that can give it a zing.
liz always keep a pot of natural yogart handy when making a currie. it will cool it down if to spicie ,drink a glass of milk with it or eat cucumber three handy hints i got that tip of a mate she is half asian and half irish she calls herself, a paddystarnie .