Posted: 27/07/2014 at 14:08
Kev.....the lower leaves do tend to die off ( a natural process ).
However, another reason could be that you have inadvertently got water on the leaves and the sun has scorched them and accelerated the process.
I am unable to enlarge your pic so difficult to see clearly. You could simply remove the affected leaves and pot on asap.
If the damage spreads further you need to consider other causes or return your plant to the Nursery you bought it from.