Possible Alexander Ritchie Cross. Help needed with worn mark

[scrimig0ur]

This cross belonged to my mother. I believe it came into her possession around 60 ago.
The makers mark appears to be "A R" . Alexander Ritchie of Iona is well known for this type of work. The year letter looks like an "n".
Any help identifying it would be very much appreciated.
Thanks in advance,
Peter
http://i92.photobucket.com/albums/l20/b1gf00t/Front.jpg

http://i92.photobucket.com/albums/l20/b1gf00t/reverse-2.jpg

[larkfield]

The marks are not clear, but the third mark looks to be the Lion Ramant the standard mark for Glasgow, in which case I would guess the second mark to be the Tree Fish and Bell for Glasgow and the fourth mark the Thistle. If the last mark is n then looks to be 1936 at which time the sponsor mark would be Iona Celtic Art a business or trading name used by Alexander Ritchie

[scrimig0ur]

Thanks for your reply. I've sent the pics of the cross to David James, who runs the Alexander Ritchie website and also to Mairi MacArthur, both of whom have written books on Iona Celtic art. David emailed me last night, and he is almost certain it is a Ritchie cross.
He thinks the date letter is a lower case "h" with a Glasgow hallmark, dating it to 1929. I'm still waiting to hear back from Mairi.
I'm going to the library to do a bit of research myself today, to see if I can find the actual stone cross it was based on.