Back when I had my MK3 ibiza cupra 1.8T I was stopped in traffic when it over heated, that turned out to be a blown fuse on top of the battery box, replaced the fuse and topped up with coolant and never had a problem. With the LCR I'd be changing the temp sender and thermostat to rule out 1st. With mine I checked the water pump and got that replaced too. Other thing to look at are the fans, I noted mine heating up in traffic a few years back and replaced the fans as small fan wouldn't work all the time, purchased them from Euro car parts, never had a problem since. With regards to loosing coolant check the pipe from turbo to coolant res, mine was leaking due to age.