sorry you're suffering dannyboy
I personally think you're better off using alternate heat and cold therapy on PF, that way blood flow to the area is encouraged - which promotes the healing process. Just using cold is good when an injury/condition is acute, but not in chronic stages which is where you are. Some soft tissue therapy would help as well - you could have tightness in your achilles/calf muscles or higher up the posterior chain of muscles/soft tissues might be causal factors.
a golf ball will help (in fact I recommend it to my clients), but targeted treatment from a trained professional can really kick start the healing process.
just out of interest, what treatment/rehab did you do in between seeing the podiatrist and seeing the physio? Often resting or doing very little won't be sufficient to eradicate an injury.
re stretches - you'll have to do them very regular, and hold them until you feel the tightness easing (rather than counting for 20-30 seconds) for the stretch to be anywhere near effective. think of a rubber band - to make it longer you need to hold it in a lengthened position for a long period of time - a short stretch and release just returns it to its original length.
I hope this helps,
Lynne

