Google says hardy to zone 8 but not in exposed conditions.
http://www.rhs.org.uk/plants/details?plantid=624
I think you are in zone 9?

Thanks Steragram, we are borderline between zones 8 and 9 so it might be worth a trial.

I would say worth a try. They can be expensive
but with the reward of the delightfully-scented flowers means they are probably worth it...
Give it shelter from any nasty wind, and from any frost.
The bees will appreciate it I'm sure.
Might also/instead be worth considering - D. mezereum

Grows very well in Limerick (my brother's garden) and in Glasnevin Botanic gardens, also in Kinsealy, N. Dublin. I have one planted in Navan, Co. Meath, but it is still small and has yet to be tested seriously. I have seen it in garden centres but certainly not common.

Thanks for all your comments, I only found two online suppliers in Ireland and they certainly are expensive but I will pass on all of this information and see if he would like to go ahead. All the help is much appreciated.