Without sounding like an idiot, im wondering. As i have completed all storylines, including DLC, i should be able to summon my sparrow instantly on any mission. this isnt the case. The game will not allow me to summon my sparrow on missions to which i shouldnt normally have it, i.e. restoration. Ive seen some of the speedruns on here for many early planet missions and i see the sparrows being used normally. How is this?

That to me sounds like a glitch in the system since you should be able to spawn your sparrow at the start in every mission but exclusion zone. I'm sorry I can't help you out any further hopefully it all just fixes itself for you.

You have to have the mission set to one of the light level difficulties. I.E Level 22, 26, or 30

You don't have to have it on the light levels since i run every mission on easy difficulty and don't have that issue.

Yeah also I was running it on 22 to test that theory as i also thought that and it isnt the reason behind the sparrow not being summonable

Have you tried summoning the sparrow as soon as you hear the audio tone (cue?) just before starting the mission? (When you are still in your ship, right around the time the screen goes black) I know it's possible on most missions to get your sparrow almost as soon as the map loads. It might be something to try.