Citroen C5 Exclusive - Rear spoiler fixing clips

[redalfaman]

I recently had a repair the the ruptured rear washer pipe (not uncommon) and broken loom connection to rear overhead brake light. Subsequently the spoiler keeps popping up out of alignment and prevents the rear tailgate opening.
My local agent tells me that the plastic fixing clips are not available and I shall have to buy a new assembly (cost c£1000!!)
Does anyone have some old clips or an idea as to how the problem might be solved (car probably worth £4K, if I'm lucky - but otherwise perfect...)
Thanks for any advice
John