I had the ill thought of adding raw lemon to my apples jam (half for ~2.5lt, in other words half for blender load), it tastes inhumanly bitter. Apart from the level of acidity which can be fixed with soda I don't know how to fix the bitterness, the lemon peel nearly causes me nausea.   Is It fixable?  If not, how can I reuse it? Chutney?  What's the mininum number of ingredients for chutney? 
I'm going to assume that 'grill' in your sense is top heat.  If so, some recommendations:   Leave the oven door slightly ajar.  This will keep moisture from building up in the oven, and steaming the ingredients.  (gas ovens always have some venting, but they can still get a build-up of steam; electric ovens will switch off if they get too hot) Get the food as close to the heating element as you can.  That will get you the layer of char on top, that you won't get if it's 6" (15cm) or more from element.  I aim for about 1" (2.5cm) from the element, although a little bit more for thick cuts of meat.  (Steaks plumps up as they cook, and they can reach up and touch the element if you're too close)  