Thankyou Debra for your prompt response.

You are correct re Ancestry tree data. In this case there are numerous dates, places etc put forward for births, marriages etc, none of which are supported by factual documentation and many in conflict with each other, hence my frustration.
I don't trust facts unless supported. I don't have any of the certificates you mention as yet but agree that this is where I may have to go. I was hoping I could avoid this if someone had already been down the same path. I had a similar situation not long ago and the death cert had very little info on it none of which I didn't already have. Very frustrating.
The entry you supplied re Williams/Excell is very promising as it fits in each detail. The name Edwin is of interest as this might provide another avenue to explore. I agree I couldn't find a marriage registration for Edward and Caroline/Catherine despite the many 'trees' that actually quote a date.
Thanks again, I will stay on the hunt. Let me know if you want any info I uncover , assuming my luck improves.
Paul (Sydney, Australia)