Thanks to all for your replies. Maybe a wierd lucky coincidence, but finding a pictorial guide to the dash panel fuse box, on the floor under the passenger seat today, led me to investigate that. There's obviously been some alterations (see attached), and one of the added connectors was loose. Testing again after reseating that and the lights are now behaving themselves! There is an after-market reversing camera fitted - but no screen. There are also two live USB leads in the dash-top storage compartment. So I wonder if the fuse box alterations could be linked to either of those? Re. missing cover. Retracting washers are far too advanced for me! Previous car was Octy Mk1 with fixed washers on bumper. Now I know what to search for, eBay has thrown up possibilities. A couple of UK sellers have them for under a tenner a pair - unpainted. So I just need to find the right paint. Thank you again for all the help.