Forester Ride Height at Rear / Down on one side

Hello

I have a 56 plate 2.0 XE Auto Forester with 92000 miles on the clock which has self levelling rear suspension. A few weeks ago I noticed that it was sitting slightly lower to the OSR side. I measured the gap between the wheel arch and centre of the wheel on both sides and the difference was about 3mm. 

Took it to my local garage (not a Subaru dealer ) and they diagnosed a soft spring on that side. I was surprised at this and had thought before taking it in that perhaps the shock absorber on that side was leaking or faulty in some other way. On the subject of shock absorbers, the one on this side was replaced about 6 months ago. At the time I did not want to pay the £364 + VAT quoted by Subaru for this part and sourced a second hand one from another Forester which was being broken for spares. This one I fitted was in extremely good condition with no leaks.

Yesterday I had 2 new springs fitted as was aware that you should only fit as a pair. Again I did not want to pay Subaru's prices so sourced a pair from another manufacturer ( Lesjofors ) and at the time of purchase ensured that I had the correct ones for this vehicle bearing mind it has self levelling rear suspension.

To my disappointment and now with the two brand new springs fitted it is still sitting slightly lower as before.

Although in no way affecting the performance of the vehicle, I am just being a bit pedantic over this and wondered if anybody has either experienced this issue or can offer some advice or have an opinion

Any comments greatly recieved

Many Thanks

Brian Benjamin