Thank you for all the suggestions.
I talked to Steve at LBM and he said the issue was with one of the Foundry Gaulish shields has a central reinforcing spine that runs the complete length of the shield and joins the raised rim that goes around the outside, this would require a split transfer.
I checked out the VVV transfers, they only come in 4 colours whereas most artist concepts show multi colours on the shields.
Cutting and trimming the decal/transfer would be a bit fiddley and I might lose my patience with it.
Steve recommended Victrix shields and transfers but as SJWi stated that is an additional cost ( £15 for 60 shields) and I am not a great fan of plastic.
Gripping Beast have suitable metal shields but again another cost incurred and the current slow postal system here in Canada would mean a very long wait.
As I paint my shields separate from the figure and then bond them on before varnishing I think I am going to try some freehand on the oval shields with the central reinforcing spine but buy transfers for the others.
I might contact Rich of TFL as he has painted Foundry Gauls and Early Germans for his new ruleset Infamy, Infamy so he might know if Early German transfers fit Gaulish shields.
Thanks again for the comments, appreciated.
Cheers,
Graham W