Thanks for all of your replies.
Although I have been playing for many years, and although I'm not unintelligent, I DO have big difficulties with music theory. I really struggle with it. Crotchets, quavers, semibreves etc just confuse me. I can play pretty well anything up to pieces with 3 sharps or three flats, but beyond that I struggle. I can play for 2 to 3 hours at a time, missing very few notes, but I often have to look up a new piece on say YouTube to work out the timings of the piece. It's just the way I'm wired..
But this year having more time on my hands, I decided to try and improve my playing, and the first thing for me to tackle is learning a number of chords. So that's why, if I come across a chord I don't recognise, I have to look it up. I will always TRY to play it if I can. I won't run away from it. So you'll appreciate that when that chord is being shown with the same notes in one book (or chord finder), and in another book it's completely different and in a different sequence, I struggle to understand why that is.
I learned C Major CEG when I was about 7 years old. I've never, ever, seen it played differently.....But I had never even heard of inversions before. Neither has my wife who sings in a local choir with a professional choirmaster /organist. She plays a Technics Digital Ensemble Piano SX - PR900. I am 75 she is 73, so we obviously weren't taught very well!
She found this amazingly funny, and likened it to the Morecambe and Wise Show where Andre Previn was their guest.
Eric Morecambe, after making a complete shambles of a piece, famously grabbed Andre Previn by his lapels and said
" I AM playing all the right notes.....Just not neccessarily in the right order"
All of your replies are useful and I can only aspire to get better with hours and hours of practice. I know some of you are hugely experienced, and I could never get to your levels of play, but it won't stop me trying!
Thank you, all of you.