Hi Steve. I confess that I'd assumed that the OP had researched that but maybe she hadn't, given that she didn't know where Sagres was. In which case: http://www.faroairportguide.com/taxis.htm

I was aware the it was 90km from Faro to Lagos but the car option seemed easier than train. I'm also hopping on a flight straight from work and will be arriving early evening so I wanted the shortest and most comfortable option to get there. I'm not really worried about the cost as we are not on a budget.
I believe there is a shuttle service between Faro airport and Lagos - is that the case? And is it easy enough to book arrange before I leave for Portugal?
If not, I will just get a taxi.