My total Sp on the dashboard and under my account worth is just over 8K but I clicked to pick up some free food and got told that I had enough money to buy my own, it claims that I have 28K, so um, anyone know what's up with that?

Did you put anything for sale in your shop? You also get some sP for posting in the forums as well. :)

Check the sP isn't in your shop till or your vault.

Ah, that explains it, thanks, I didn't realise that I had to actually collect the Sp from my shop, you'd think it would just transfer over.

Nah it doesn't, because there are shop till-related achievements (have so much in your shop, and there are tiers which get higher and higher).