[Stripey_cat]

I sowed my seeds last night. I wasnt sure how many seeds to sow of each type, so I sowed 4 tomato plants and 2 of 3 types of aubergine and 2 of 2 types of pepper and thought I would sow another lot of same number next week or week after so not all flowering at same time. Is that a good idea?

They're plants that flower and crop over quite a long period anyway; gluts usually come because of the weather.  It won't do any harm to stagger the sowing (and if you have a failure you can resow without problems), but it probably won't make much difference to your harvest dates.  Of course, if you have limited space in your propagator it'll solve that problem.

Thanx DD looked up the aluminium foil but it is a heated propagator I got so shall I just wait until the seeds have germinated and then put the foil behind them when growing on inside before they go to greenhouse?

That's right.  As soon as they're up, move them out into good light, and put a reflector behind them.

I did my leeks also, in a cat litter tray and also just a normal cell tray just to see the difference in them. I am going to start them in my conservatory (no heating on in there) cos I think the greenhouse might be too cold just now.

Stick a thermometer out in your conservatory: it can get quite warm with heat coming through the house-wall.  But, yes, an unheated greenhouse is probably very cold at the moment (at night at least - my Mum's was 18C in the sun the other day).