So this is how I'm doing it. I soaked all the bottles and parts and all the breast pump parts and milk storage containers in water and washing up liquid.
I air dried all the parts before sterilising them. I then left them to dry whilst in the steriliser before putting them all in seal-able plastic bags and then back into the original box that I first bought them all in.
I have also kept the bottle teats, I know it is advised not to, but as Ben wasn't totally bottle fed, I plan to check them before we use them on the next baby. Will also be checking that all the bottles, parts and pump are okay to use again when we get them out ready to use, whenever that may be.