Here's a pic of a nailbrush:
They're cheap and can be found at supermarkets. I said a nailbrush because the bristles are firm enough to scrub, but soft enough not to damage the surface.
I also apply RO with a latex goved hand...it works the best for me.
Your leather sounds exactly like mine was...it was very dark blue pigmented leather which developed cracks, especially the front seats, and were stiff as a board. Now they're very soft.
I can only speculate about your situation, but I do believe applying the silicone-based dressings have caused your present problem.
The Lexol building up in the cracks can reduce absorption, and the rear bench has recently been TWed which will form a barrier.
Try the nailbrush and see what happens, then come back to us with your results.
Have a look at these links:
http://www.leatherique.com.au/leathers.php http://www.germantechnik.com/showthr...s=&threadid=82