Hi, I've got some experience of this on my S1 and have found a fix that works for me, assuming battery is healthy, I use an Odyssey gel model:
1. Have the battery on a smart charger, (e.g Ctek mxs 5.0) on a timer for 4 hours per day, on an ongoing basis. 4 hours a day limit prevents frying of the cells
2. When more than 10 clicks to start, spray some WD40 around the gap on the perimeter of the green start button, then with ignition off, about 30-50 repeated pushes of the button to work it in
3. Car should start within 3 attempts.
4. Repeat step 2 as needed , normally after an extended period without use
Hope this helps
