Just a bit of info if you're looking to get a spider ready for "summer" - whatever that may mean this year.
Having had a couple of issues with poor and broken rear screens I happened on a place near Southend airport who are happy to help, and replaced the plastic screen in my spider (now my brothers)
They'll replace the plastic for £80 if you take the screen into them, but even better take the car to them and they'll do the whole thing start to finish for £125
The only rider to that is that because the allen bolts that hold it in are a pain in the arse and usually at least a couple round off, then the new screen will get re-fixed with rivets in the same way MGF's are fixed. And if it ever needs doing again then it's going to be a case of drill off rivet heads, re-rivet
So, if you want to keep the car all original, take it out yourself - good luck with the bolts etc, if you just want it to look right, pay the extra £45 and it's over and done
They're called Hoods Galore, speak to Simon Tolworthy, 01702 547 999 and mention that you saw it on the Alfaowners forum with the prices as shown :-)