Assistance with Shopify Store

Hello!

Here is what i would like to be done for my site Elizabeth Eve

Theme updated (without removing the customer bundle buiilder you did before)
Nested menus to be working - currently not working as i think theme is out of date.
Can we make the discount code box more visable on mobile (currently it is in the order summary) and it feels quite hidden.
mobile view of checkout need editing as is messy
The bundle builder and cart pages are very slow to load - is there anything you can do to speed this up?

www.elizabetheve.co.uk

Would like these fixes asap
thanks

B