Suggest you try Peter Truchan at 'American Dreams' (Gloucester) or Adrian Dromey (located in Lincs; not sure exactly where)…… anyway, they are known to 'separate' acrylic roofs from C6s and sell them separately from the car. No law against that, but it's a bit irritating for anyone buying a C6 with RPO C2L, only to find the acrylic roof panel is missing.
(RPO C2L = Dual removable roof panels, i.e. one body color, one transparent; RPO CC3 is just the one transparent unit).
J. C. (1911)