Is it possible to slip out the corroded cross members that go across the way on a series 3 rear floor? they look riveted in some way?

compressor only works with all the doors shut

Hi I have just purchased a 1974 series 3 for restoration. It has a galvanised chassis but the bulkhead is shot. I researched parts availability and help sites and found Landyzone so hopefully I will get answers to my many questions as I start the restoration