Lettuce won't germinate well at those temperatures. They require temps under 80.

Here is a link that might be useful: germination chart

Just in case US readers are wondering about rocket. That's arugula. I call it rocket too but have learned the alternative name on these forums. Apparently it needs 40 - 55 Fahrenheit to germinate ie pretty cool by your standards. A nice warm spring day by mine. I don't know about the light thing. I just sow in a shallow groove. Seems to do OK.

simpson is a great cool weather lettuce, bolts very quickly - so I would wait on that.

Arugula. it bolts too, but you may be able to keep it clipped until the cool weather, however, it will get a very strong taste quickly in the heat - not sure if that will abate when the temps go down.