Below is a link to removing the washer tank/getting at the pumps, however as it seems your windscreen squirters work as I suppose does the rear glass squirter, that the main pump is OK.
It may be that your headlight washers are OK as well. Yes, there is a separate headlight squirter pump, but they do not squirt everytime you operate the windscreen squirter.
The spraying of the headlights is on some kind of program, (per below), where all sorts of variables have to be in place. The headlights being on is only one of them and if they were, something related to mileage and windscreen wiper on time is also involved.
Head Lamp Wash Only (No Wipe Function)
The headlamp washers are only active when the headlamps and ignition are switched on. If the washer reservoir fluid level becomes low, the instrument cluster sends a message, via the CAN bus, to the CJB, which suspends headlamp wash operation to preserve washer fluid in the reservoir.
With the ignition and lights on, headlamp wash is activated on the first operation of the wiper column control switch in the wash/wipe position. The CJB then suspends headlamp wash activation for the next 10 minutes and four operations of the wash/wipe switch.
The CJB monitors the operation of the wash/wipe switch and maintains a counter to restrict headlamp washer operation to every fourth operation of the wash/wipe switch in conjunction with a 10 minute timer. The timer prevents a second operation of the headlamp washers within a 10 minute period. Should the washer switch be activated for more than four programmed wipe requests during the 10 minute period, the headlamp washer will remain disabled. Only the next consecutive programmed wipe request, after the 10 timer has expired, will the headlamp washers be enabled. The counter and timer are reset when the ignition is switched off.
When headlamp wash is active, the CJB energises the washer pump twice per cycle. The headlamp washer pump is powered for a 0.5 second period.
https://www.disco3.co.uk/forum/replacing-washer-bottle-60402.html?highlight=washer+tank
The link below is to a 17 page LR pdf re the operation of the wiper systems.
https://www.disco3.co.uk/gallery/displayimage.php?album=3801&pos=2