Omni roof vent covers

LizIT

Sorry I listed this in the wrong forum but hope someone can help. The Omni roof light cover on our Bailey has mysteriously dissapeared... ok blown off, despite being fully closed (we check and check and check again before travelling anywhere). Does anyone
know where to buy replacements as I can't believe what Bailey want for this piece of cheap molded plastic that obviously isn't strong enough for the job.
https://www.bailey-parts.co.uk/Product.aspx?PartNumber=1160020  I'm thinking I might just replace complete with a Heki but you can't leave them partly open but still locked and rain
proof in the same way as the Omni. Thanks