Can I substitute a small amount of say, hot english mustard for Dijon, or is there some other alternative. (Of course I will get some soon, but right now i have none, and was wondering if i can make do with something else)
Dijon has a strong taste from the liquid they use in it (it's not quite vinegar, not quite wine). I'd probably try a blend of some other mustard + a little white wine vinegar (not white vinegar; white wine vinegar) or champaigne vinegar or apple cider vinegar. (Maybe even a dry white wine, if you have that on hand).
If you have dry mustard powder, and some time to let it sit, you could also try making your own; most of the recipes online seem to use a dry white wine as their base, a few use white wine vinegar.