Thank you for all of your input :)
To me, it is Lyle that rhymes with Kyle.
I agree with the American sounding Ellen
Tate & Lyle is the only association for me really, one I am not too bothered by. - Cake - I absolutely love Tate and it would be my first choice but unfortunately, it is disastrous with surname. Devastated.
And to me, I don't think it sounds opposite to posh and don't think it would to my nearest and dearest either, so can cross that out.
As it happens, a friend of mine is due in the same month as me and told me her boy's name (should she have one) and it turned out to be my Number 1 name choice. Turns out she is having a girl and that name is now freed up again for me to use (she knew I liked it too so not stepping on toes!) So Lyle is currently in 2nd place.
Thanks again 