Q.Heavy Soil/Poor Drainage
I am continually digging up and then digging in compost to try to improve the heavy almost clay like soil we have. I have lost so many plants it is becoming a joke. I am wondering if I should try some sand, or maybe some stones/shingle which may help to break up this mud.

Certified GKH Gardening Expert
Improving clay soil takes time but you are on the right track. It can actually become very fertile once the structure is improved.
You might want to get a soil test to see if there is any nutrient deficiency or pH imbalance that needs to be corrected. This could be part of what's been killing your plants.
Compost, mulch, and the use of cover crops (crops that you won't eat but that will improve the structure with their root systems) can all help. The following article gives more ideas:
https://extension.missouri.edu/news/DisplayStory.aspx?N=1815
Clay soil is also susceptible to becoming compacted, so it's best not to dig it up too often, instead letting plant roots do the work.