Jaguar Repair Problems? Ask a Jaguar Repairs Expert.
I have had many drain tubes block up to the point of water entry in the cabin.
This is a MUCH MUCH cheaper option.
If you find the drain tube from the firewall side of the engine bay, get a ziptie or similar flexible piece of plastic about 300mm long, stick up the drain tube with a wiggle around. If the water comes pouring out at that point continue with the ziptie until the flow stops. Hopefully the cause which could be tiny leaf litter or insects etc has flushed out with the water.
I have never needed to removed an evaporator case for a blocked drain tube.
I used to love playing a trick on the apprentices for this condition, they got wet every time.
Hope this helps.