Land Rover Repair: engine damage do to overheating?, temperature gage, head gasket

Question
I own a 2000 Disco 2 with 105,000 miles; Today I notice my temperature gauge rising a bit, then going down to the normal position (in the middle).   When I got home the gauge reached to top mark, but did not hit the red zone.  Once this happened, I pulled over and shut off the engine.   I checked the coolant and noticed it was empty.  I few days ago, I notice the smell of coolant in the air.  From reading other forums; it appears that I may need a head gasket(s) replacement.  My concern is with any damage to the engine caused by overheating. The engine only ran with temp gauge on high for no more than a half a block.  Would this be enough to cause a cracked block or a dropped cylinder sleeve?  Is the car drivable in this condition (once I add coolant)?

Thanks

Answer
With that short of a time I doubt you did damage, make sure to tell the mechanic that does the work exactly what happened so he knows to check for slipped liners.  With no water it is possible the temperature gage was not reading the true temperature of the engine so it may have been hotter for longer than indicated.

I would be very cautious about driving it, only if absolutely necessary.  The cost of a tow is nothing compared to a new engine.