Edenbridge is heavily sloped. 
Slope, MIXEDMODE, and curvilinear interval restrictions with Zwift are described in detail here –
The Ultimate Guide to Training with Xert and Zwift – Xert
TL;DR – Substitute an alternate workout that isn’t MIXEDMODE or includes curvilinears or use EBC phone app for SMART workouts with those types of intervals.
No need for a post-workout Goldilocks survey with Xert. 
Workouts scale to your ever-changing fitness signature.
Click here for an example of a scaled VO2max workout on Xert.
When your signature is dialed in you should be able complete most HIT works at 100% intensity in AUTO mode (EBC) whenever your Status stars count matches Difficulty diamond count. Workouts below or above your current count will be easier or harder to ride.
Here’s my original all-indoor experiment on Xert EBC at 100% compliance –
Pre-Base to TED; 120+ days; 100% recommended workouts completed at 100% intensity
I have since moved on from the 100% compliance mindset 
and come to realize there are numerous ways to achieve the strain goal for the day.
On a tough structured workout that might include skipping an interval now and then or slipping into Slope mode to do my best. Or use Slope for an easier RIB (rest-in-between). Plus, I can make up missed intervals by following XMB (Xert Magic Buckets) guidelines to address any unfilled low/high/peak buckets during an extended cooldown.
Or I can free ride to start with (no workout selected) and use XMB to accomplish the day’s XSS goal.
As to whether you have the option to do this while riding in Zwift world will depend on your equipment setup.
Do you have an iOS or Android phone?
Do you have a Garmin Edge or Hammerhead Karoo head unit?
Does your trainer bike have a separate power meter?
Do you have a laptop?