First of all many thanks to Dani Chankhour for helping me to identify and fix the problem.
Obviously from that sentence you can tell Image Resizer works as per the WA sales pitch !
I feel a couple of lines to explain the issue may help others.
I have a plesk interface to my hosting accounts, I am no means an expert with Plesk, but I do know 'what I need to know' to run my sites.
So for those using Plesk as ther interface to their hosting accounts, go to the hosting set up for the domain and looked at the: PHP support (run as apache, PHP 'safe_mode' on ) ... make sure the safe mode is NOT TICKED.
On my working site it was unticked on the none-working site it was tick, removing the tick it all worked perfectly.
and as proof .... www.ratpack.biz
Once again Thanks Dani ..... Web Assitance worthy of the name WebAssist !!!