Nice twist to the end of this query!
So after checking and carefully explaining to accounts at my office what the cheque needed to say, they then still got it wrong (for the second time!) and I ended up with a cheque saying "First Great Western Ltd".
As I was out of time and needed to renew before the yearly price increase I checked via phone with
FGW▸ asking if variations would be accepted. "No" was the clear answer given.
So I went to Reading Ticket Office armed with my credit card and took my cheque still just in case. I have to say the staff at Reading Ticket Office were very helpful (especially with helping with the Void days too) and were adamant that the cheque was fine and that variations
are accepted!!!