Thank you so much for all the suggestions, I appreciate it so much!
To answer a few questions, DD is 28 months. I bought a double buggie but DD refuses to go in it. The comment made about 'going rigid as a board' had me in stitches, I'm sure every parent has delt with that 😅 My DD does that if I try to get her to do anything she doesnt want to do.
She mostly walks because she refuses all of her buggies now. Before she turned 1 we were always out and about, she loved it. She loved people watching and often sat in her buggie laughing hysterically because someone walked past up. I loved it!
Now though she would barge past someone like they're not even there, she has no sense of danger so being out is a constant fight because she wants to run on the road and gets frustrated because I wont let her. We walked into a shop to buy her a new jacket yesterday and she didnt like that we had to go in a specific door and lost control so we had to take her out.
Yes I do explain to her everything we are going to do as well as repeat it over and over as we are doing it so she knows what to expect. It's like she doesnt understand or doesnt listen or maybe just wants to do what she wants to do because it doesnt really help. I am going to try photos of familiar places to see if visual instructions work better.
@FakeCutlassesAreAGatewayWeapon I dont think you're patronising at all, I really appreciate your advice and I'm grateful you took the time to post 
@goisey Yes, I think some of the difficulty is DD having her own agenda, but i have also noticed anxiety.
I recently took her for an radiology test to rule out hearing issues (she past). DD was fine and happy but became distressed when entering the test room. The whole test was conducted with DD thrashing and screaming. She stopped (like a switch being flicked) and was happy again as soon as we left the room. Then we walked to the stairs, walked down 3 steps and she started thrashing and screaming again. I have no idea why, although I have noticed her getting stressed at home if her foot misses a step and she will run and touch the step she missed (I take her hand as we go down but she lifts her feet and doesnt walk down properly). Anyway we get to the bottom and she is suddenly back to happy.
The thing I'm confused with is that she seems to seek out sensory things rather than avoid it. My DS avoided sensory stimulation as much as possible and would become physically ill. DD, even as a baby, gets anxious and becomes distressed if the car stops which means we often avoid driving places we know we will be stuck in traffic.
I like the idea of a weighted blanket, where would I look for one?