Brought an Audi q3 65 plate from a dealer in February. Been having issues and can’t connect phone or use the satnav. Tells me to contact audi to sort..

I’ve looked into it and seems you need an sd card. Do I have to just buy this and it’s sorted or other things to do? Is it easier to just take to Audi to sort?

If you've had these issues since you bought it, it sounds like the dealer is fobbing you off. Under consumer law items being sold should be working and for an acceptable amount of time. In the first 6 months the seller has to prove the fault wasn't there when sold. After 6 months the buyer has to prove it wasn't working.