Hi PP,
I have amended my layout slightly so it looks like the diagrams below:

- latest1.jpg (72.14 KiB) Viewed 1878 times

- latest.jpg (94.25 KiB) Viewed 1878 times
In case you want to use them, I have attached the icons I use (red/green/black) circles and squares. Circles means GRO Index and squares means certificates. I have included green circles and squares with the numbers 1, 2, 3 and 4 inside.
To display the Index (circle) Icons, I have the following expressions, one after the other in the BOXES tab of the Diagram Options:
=IsTrue(%INDI.FAMS[1]>MARR.SOUR>_TYPE% = "Index - BMD Index")
=IsTrue(%INDI.FAMS[2]>MARR.SOUR>_TYPE% = "Index - BMD Index")
=IsTrue(%INDI.FAMS[3]>MARR.SOUR>_TYPE% = "Index - BMD Index")
In your case, you will need:
=IsTrue(Exists(%INDI.FAMS[1]>MARR.DATE%) and Not(ContainsText(%INDI.FAMS[1]>MARR.SOUR>%,"Certificate Marriage",STD)))
=IsTrue(Exists(%INDI.FAMS[2]>MARR.DATE%) and Not(ContainsText(%INDI.FAMS[2]>MARR.SOUR>%,"Certificate Marriage",STD)))
=IsTrue(Exists(%INDI.FAMS[3]>MARR.DATE%) and Not(ContainsText(%INDI.FAMS[3]>MARR.SOUR>%,"Certificate Marriage",STD)))
and for the Certificate Icons, you will need:
=ContainsText(%INDI.FAMS[1]>MARR.SOUR>%,"Certificate Marriage",STD)
=ContainsText(%INDI.FAMS[2]>MARR.SOUR>%,"Certificate Marriage",STD)
=ContainsText(%INDI.FAMS[3]>MARR.SOUR>%,"Certificate Marriage",STD)
To change the TEXT scheme so that only marriages show, add these three templates into the EDIT TEXT SCHEME on the TEXT tab of the diagram options:
=FactText(%INDI.FAMS[1]>MARR%,"CT","E_M: _ in _")
=FactText(%INDI.FAMS[2]>MARR%,"CT","E_M: _ in _")
=FactText(%INDI.FAMS[3]>MARR%,"CT","E_M: _ in _")
If you need any help, please ask.