Weebly website to speed up

I have a weebly website (www.cardiologistuk.com) that is slow to load. I would like to speed this up. I have tried to keep pictures small but the have plugins with google analytics, google tags, zotabox, cookie manager, boom form, and google maps. Also I think the Weebly theme has a lot of unnecessary things. I would like streamline the theme, streamline the plugins and really speed up the site.
Anybody able to sort this out with messing up the look of the site please.
(and when removing/changing the theme I would still like to be able to use the site builder to make changes in future)