Hi Barry?,
If your car has indeed got the concentric clutch slave cylinder, then this is situated inside the bellhousing and any fluid leaking from it will flow downwards and find it's way out at the bottom of the bellhousing, close to the end of the engine sump. It shouldn't really get on or affect your starter motor unless it's been splashed around a lot.
If you try feeling brake fluid between your fingers, it'll feel less oily than engine or gearbox oil, plus it should still be relatively clear, same as new brake fluid, unlike engine oil which goes black fairly quickly (especially on a diesel).
You don't need a jack to do a quick check on this -just lie on the ground, reach in and feel whatever is leaking. (or park with 2 wheels on a kerb, to raise one side of the car and slide underneath).
I've got a 2008, petrol,1.4 90hp Bravo.
There's only 14,000 miles on mine (I usually use another car) so have only carried out servicing and a timing belt change.
Maybe your 1.6 Multijet is the same as the 1.9 as regards the clutch?
The official Fiat manuals seem to go in for too much removal of items when doing repairs - on my car (1.4 petrol), they say the engine and gearbox have to be removed as one unit, then split to work on the clutch. Whereas, on most cars, there's usually some way of removing the gearbox on it's own, saves a lot of time and effort. Best approach might be to try to find someone who has done a clutch on your exact model and ask them how they did it?
As regards the cost of changing the clutch and slave cylinder - 800Euro sounds like a rough estimate i.e. 400 for parts + 400 labour. Maybe ring a Fiat main dealer and get a quote, then ask for a breakdown of parts and labour/how many hours. Now, knowing the cost of genuine parts, you can see if aftermarket cheaper parts are available and then armed with this info, try an independent Mechanic/garage for another quote.
One other thing to consider if doing a clutch, does your car have a dual mass flywheel (DMF), if so it might also have to be replaced, bumping up the cost.
Whether it's worth spending money on your car, I can't say. What is the general condition, mileage, etc.? Do you like the car? Do you think you'll get a decent amount of reliable use from it after changing the clutch? Maybe someone might take it 'as is', as a trade-in (they can fit a clutch much cheaper than it'll probably cost you to do it)?
Cheapest option:- make sure that it is indeed the clutch slave cylinder that has failed, remove the gearbox on it's own (if this is possible), fit a new slave cylinder, leave the original clutch alone if it was ok up to now and reassemble. (i.e. minimum work and parts, just enough to get the car back on the road). If you decide to tackle the job yourself, I'd say best to set aside a full day if you haven't done this type of job before and make sure you have the necessary tools, you'll need a suitable large socket + bar for the driveshaft nut (it might even be a deep and/or 12 point socket) and eTorx? sockets, best to have a good look at all the fasteners you'll have to undo before starting the job.
Al.