Classic Bluey, look at these replacement sills. Seem quite resonable for the price.
http://www.yrm-metal-solutions.co.uk/
Looking at having a set shipped over for "Miles" currently the only sills in the truck are my sliders
POR-15 is a great product. also look at this product it is low VOC (good? for the environment)
http://supertherm.net/home.htm
my 2 cents
Mike