Here we go again! Not content with putting cornflour in her lemon curd and pushing tinned fried onions, she now sest her sights on ruining out of all recognition one of the greatest Mediterranean dishes ever invented - ratatouille.
I shall start at the beginning; what she has here is oven roasted vegetables, not ratatouille. Ratatouille is a very traditonal Mediterranean dish of stewed vegetables - so is done on the top of the stove. It has tomatoes, onions and courgettes in it, garlic, oil and seasoning. There is no need to peel the tomatoes. If stewing the three main veg together, be prepared for it to go a little mushy it's what it does; if you like your vegetables firmer, then stew each separately and then combine. It's one of those dishes that improves from being made the day before and re-heated too.
As for Delia's 'recipe' - modern varieties of aubergine and courgette have had any bitterness bred out of them, even the older varieties are no longer bitter, so no salting and draining is required for the courgettes, and the aubergine if you really must include it. No peppers (they go into pepperonata, a completey different dish, but worthwhile making too), or basil, or God forbid, coriander seeds, crushed or otherwise.
Just saying lol. Rant over, thankyou for your indulgence :)