Sailtime.
Where are you?
To place on pushpit.....
You will have to use SS Bimini fittings from Whitworths? also get SS tube there.
Square SS will come from a steel supplier. Use SS U bolts, a lot cheaper.
While WW are a bit dearer than a SS fitting supplier probably the easiest place to get fittings.
Get a new panel off ebay. 20 watts is too small, should be around the 50 plus mark.
Be careful as a panel just slightly bigger maybe lighter in weight [check tare weights] but not that much larger in size.
Have a look at my blog [link below] for 2011, you will see SEAKA's small inadequate panel there,
or search posts here on this site as there has been discussion on this before.