Yes, the 'ECON' gauge is an econometer, or to be more precise a vacuum gauge. It measures vacuum in the inlet manifold to show how much the throttle is opened compared with engine load.
When you start the engine and leave it ticking over, the gauge should be to the left in the green sector. As soon as you drive off the gauge should move towards the yellow sector, and if you floor it it will move into the red.
At cruising speed the idea is to keep the gauge in the yellow sector, or if at all possible in the green. I find on a flat road, in 5th gear at about 70mph it will sit at about the three quarter mark on the yellow sector.
The heavier the load on the engine, i.e. flooring the throttle in top gear or hard acceleration, the further into the red the gauge will go.
As Dazzdog mentioned though, the 45 doesn't really need an econometer as it's pretty frugal however you drive it! However, drive with an eye on the econometer and you'll be amazed at what fuel consumption you can achieve. Recently I did 400 miles (mainly on a long run of 300 miles) on £26 of fuel. I worked out that my little old Fiat was doing 62 mpg!!!!!
I tried to keep out of the red zone and was rewarded with fuel consumption that would shame a lot of modern cars.
If your gauge is pointing the yellow/ red sector at tickover then something is amiss. It should be pointing low down in the green sector. There is a little sender unit for this, which is normally located next to the coil. It has two wires coming out of it, plus a vacuum pipe that runs to a t-piece connected the inlet manifold to brake servo pipe.
First thing to check is that the vacuum pipe is not split or leaking. If it's ok then you can try adjusting the sender.
On the top of the sender you will see an adjusting screw and locknut. With the engine at tickover, loosen the nut and turn the screw until you get the ECON gauge pointing low into the green sector. If the gauge reads higher when you turn the screw, turn it the other way! If this doesn't work, then the sender is probably faulty. If it does work and the gauge is adjusted, tighten the lock nut and check the gauge operates correctly under normal driving.
As for your non fuctioning temperature gauge, first locate the sender, which on the FIRE engine is located on the back of the engine block, near the alternator.
With the ignition on, remove the senders wire and earth it on the engine block, or connect a piece of wire to it and connect it to the battery negative '-' terminal. If when the wire is earthed the gauge shows maximum, then the fault is with the sender. If the gauge DOESN'T move, then either there is a short in the wire from the sender to dashboard, or the gauge itself is faulty.
By the way, welcome to the realms of mk1 Uno ownership! They are cracking little cars, and it's nice to know my 86 mk1 has others on the board for company