Water Pump Change?

I've just purchased a 2000 MK2 Mondeo 1.8 Zetec-E

There doesn't seem to be any flow back into the expansion tank from the return line.

Always the car doesn't get past 1/4 the way up the guage so it's clearly undercooling.

I'm going to replace both the thermostat and water pump. The Thermostat was the easy bit.

Problem seems to be the water pump. I understand it runs off the aux belt along with the alternator...

First off what tools do I need to take off the aux belt, is there just a tensioner which needs to be slackened or is there a bit more to it than that?

Also where abouts is the Water pump located within this area of the engine?

I've heard bits and bobs apparantly driver side wheel off, splash guard off and it's a piece of cake to change? Might change the belt which I'm there as there was power steering fluid leaking on it from the pressure sensor which has been fixed...

Help would be appreciated as I'd like to get the car sorted tommorow...