Freelander losing water

Hi. I've been given an S reg Freelander (1.8 petrol) from a friend. I have been told the head gasket is 'on the way out!'. He also says the Thermostat has been drilled? Have started it a few times as it is currently off road and it always needs about 5 litres of water pouring in to it. Once this water has circulated and any airlocks have been pushed out it runs fine (well over an hour), the water level remains constant and it doesn't overheat . The temperature gauge sits just below half way. However when i start it again, say the next day it needs water pouring in again.
I'm new to Freelanders so any help would be appreciated, although i understand this engine does have design faults. Has the head gasket gone and is it worth fixing?

general view-burn it,scrap it or if when you strip it the liners have not moved or head gasket hasn't burnt into head-skim and back together

It depends where you're losing the water from. If you've got water on the floor after you've parked up it's possible you've not got hgf and a pipe could be split or leaking.

However you could have HGF and a leak at the same time.

The key is to find where it's leaking from, then you'll know more. Check all pipe connections and the quality of the pipes.