Avoid thickening the gravy with flours or gravy granules, there is plenty of flavour in the gravy. To thicken the gravy you can either pass some of the cooked vegetables through a sieve, blitz them with a blender, or heat some of the gravy in a pan on a high heat to help evaporate some of the fluid.
Dumplings are high carb and are not tolerated well by most ladies. If you try dumplings use real suet and wholemeal flour. Make small dumplings and use these as your main carb of the dish (so avoid too many root vegetables, grains and pulses).