Hi, I don't know about products specifically for c-section scars, but a few years ago I had surgery on my face and the surgeon recommended I use silicon gel on the scar to help it flatten and fade. Unfortunately it wasn't available on prescription and it was quite expensive. But I used the gel twice a day for several months and I have to say the scar did fade quickly and now is almost invisible. I used Dermatix silicone gel, but there are quite a few different formulations on the market. www.chemistdirect.co.uk/dermatix-silicone-gel_1_6446.html
there is scar reduction gel in sheets/patches that is really good, and does work. There are a few brands about. I think I paid about £20 a pack. The stuff I used, you can cut it to the appropriate size, wash it daily and reapply until it gets too grubby or worn. Have two or three pieces so you can wash the skin and change the patch during the day/night. It would not look very attractive on exposed areas.
It is tacky enough to stick to the skin, but in some places clothes may rub it off so you might give up, unless you can find some sort of stretch bandage thing to hold it on. You really do have to use it every day, for weeks and weeks, so you will eventually get fed up with it.