Really be very very careful when using even Autodoc, I bought front and rear road springs for my wife's 2015 VW Polo 1.2TSI 5Door, it was Lesjofors springs that I was wanting, fitted the rear springs without comparing with the VW originals, the car sits maybe 10>15mm lower at the rear now. THEN and only then, I dug deeper, Lesjofors do not provide rear springs for that car, just for 3Door and GT! So, I checked up on Sachs website, got my facts, and ordered a pair in from ECP, they came in a Sachs box, but curiously the only part numbers on the label were Lesjofors numbers! I contacted ECP HQ and they said to just request the Sachs part number that you know is correct, local ECP not interested in that at all, so springs were handed back in. Now, this is the second time that I've ended up with the wrong Sachs items for this car, I ordered a pair of new Sachs rear dampers from ECP but they were not what Sachs says suits that model of Polo, so again ECP HQ were contacted and that time they gave me their stock number for the ones that Sachs said suit that car, so I swopped them over.
Events have claimed too much time, so I have not yet swopped the front dampers and springs, but I'm hoping that they are okay! My plan here is to "refresh" the front and rear suspension etc at 9 years/50,000miles in time so that I don't end up having a spring break on me at an inconvenient point in time! The rear springs that I took off that car were both rusting badly at the same point - which is where the springs are suspended from when getting spray painted, when I got the new Lesjofors springs from Autodoc, I noticed that all 4 springs had a bare area - again I'd think from where they were hung while being painted, so I've sorted that out on all of them.
I can't speak from experience of Leons, but certainly on any Polo and
Ibiza I've worked on, you need to retain the plastic "basket" dust guard retainer from the original VW Group front strut and the VW Group dust cover from the original rear dampers and also the spring clip from the top of the piston, for use on the aftermarket struts and dampers.
So, if you are replacing the front struts, I'd hope that you replace the springs as well before they end up snapping, and the top mounting and bearing - along with all the bolts and nuts that have been removed.
Edit:- I've had front spring failure on a 2002 Polo in maybe 2006 or 2007, rear spring failure in 2009, in a 2009
Ibiza I had a rear spring cause an MOT failure in 2015 and a front spring failure in 2017, so that is why I've chosen to try and avoid it with this car.