Ground/Earth connection is via bullet terminals to a ring terminal to a nolt/nut through front edge of inner wing vertical panel behind the headlight, possible a broken wire or a faulty light unit.
Nope they are proper rubber bungs for that job
LR part ERR5034 Plug camshaft oil feed x 3
https://www.johnrichardssurplus.co.uk/land-rover-camshaft-rubber-blanking-plug-etc7708-use-err5034.html
Replace the core plug,
Rubber bung missing from camshaft bearing oil drilling, there are 3 of these on that side of block
Check the pipes are not cracked or rusted & replace the rocker cover seal under the nut
Could be for dim dip, if there are 2 blue/red trace wires join those with a jumper wire or the dummy relay then dim dip will work
but thought that was located behind instrument pack as on 300tdi defenders
Remove the rubber covers I engine bay, then 4 nuts that secure turrets to the fixing ring, then lower damper attachment & lift turret & damper off the spring mounts