Hey Albert,
The new QRH is a bit strange at first. Especially the summaries have become more or less useless, because the VAPP and the Landing Distance tables are gone and one has to refer to the IFL Sections, as you stated. So what is the point of the summaries now? Right, they are frakkin' useless now
In the QRH version I am looking at, I see for a Slats = 2 G+B Hydraulic Failure in the IFL Failure Tables a delta VREF of 15.
So, what you could do, is to set up the FMCG for arrival and set on the PERF Approach Page Config Full. You should see your VLS speed there, or you could get the VLS speed (VREF) for Config Full from the IFL page in the QRH, for the estimated landing weight, if the FMGC hasn't been set up for the approach yet.
Then, for the case of a Slats = 2 case, the 1. increment to the VLS Conf Full is the 15 knots from the IFL Table (Hydraulic Failures). Now go and check the IFL table for the approach speeds. You will see, that for a delta VREF of 15, you might have to increase the approach speeds a bit further (1/3rd of the landing headwind). However, the total correction of delta VREF and the approach correction should not exceed 20 knots. So, let's say, the headwind is 12 knots, the VAPP would be = VLS Config Full (VREF) + delta VREF (15 knots) + approach correction (4 knots).
If the Headwind was 21 knots, then the approach correction would have to be limited to 5 knots.
For the final FMGS set up, you would select in your case then Conf 3 and enter your calculated VAPP into the PERF Landing page. However, if I am not mistaken, Airbus recommends to fly a selected speed when either Flaps/Slats are jammed.
For the landing distance, you would not have to increase it because the approach correction was 1/3 of the headwind. If, for any reason you added a few knots on top of the approach correction in -let's say calm winds- then per the IFL Hyrdraulic Failure tables you neeed to increase the distance a bit (plus 180 meters according to my QRH)
Hope that helps!
Ah, Airbus...
