Thanks for the suggestions. It's not a big space and I like to grow mostly veg, herbs, cottage garden flowers. There is a very slight slope so maybe I should just write off the end where it has puddled the worst.
Would it help if I put a load of straw down to soak up the water at the wettest part - then compost the straw when it starts to rot down ?
Build raised beds. It will not solve the drainage issues but will help the veg, herbs and flowers etc to grow as their roots are raised out of the worst. I use old pallets, stain them and they are strong and as you add soil it works well and is productive. You can easily flatten them if the owner wants them removed.