Now what have I found?

[MackemPete]

Found this while installing clear indicators. Its inside the passenger side light access hatch.

[ukkid35]

That is a typically rusty a/c drier. Does your aircon work?

[RichV6]

air con filter drier unit together with pressure switch

[MackemPete]

Thanks for the info.

It did before the car was taken off the road. Why do they have an open air scoop under the indicator lenses leading into this area? Does it serve any purpose other than to fill it with rain?

[Tanguero]

It provides the fresh air feed for the heater i.e. the cold draft round your feet. Blocking it in winter either with a tennis ball stuffed into the hole or a sponge pushed into the part where it narrows above the wheel arch is common.