Paintwork problems MGF - help please

[CandyMansing]

My nubby has an S reg MGF (1998) and has now got some scratches on the bodywork, thanks to some unknown lovely people! He knows it's Tahiti Blue and tried to get an aerosol to touch them up (they're not that deep) but it's not the right shade and he's been told there are six shades of Tahiti blue.

On the advice of a local paint and dent repairs socialist we know and trust, we tried a local branch of a national paint mixing company, but they denied having any paint swatches and said it wasn't worth their while looking into it because of the small amount involved! So effectively they simply didn't want to do it and refused.

Can anyone help with advice on how to get the exact shade to match the paintwork and where from, at the lowest, reasonable cost or method required to do a decent job.

Thank you