Really slow response with Upfront activated

Hi

Upfront is really slow. Just visiting the site with Upfront active gives load times of 10-20 seconds (sometimes 30 seconds!). The Editor is equally bad but I can partially appreciate why but I think it should be faster.

I do have MarketPress installed so some delay is to be expected there but none so bad as when Upfront is active on its own or with MarktPress.

Have used and tested other Builder themes on variations of this site but they all work much faster as do the default 2014-2016 themes.

Have tried disabling all plugins and it’s definitely Upfront with Luke&Sara theme, see results of running P3 Plugin Profiler (plugin) or tools.pingdom.com

I realise I could use caching, minify, etc. to help but that is not the main problem. Something is causing massive delays of Upfront in use (logged in or not) and that needs curing.

All caching and speed optimisations are off while I develop the site.

Single site, not MU, site access granted, you can try anything on this site, I have a full backup.

Someone’s help would very much be appreciated.