ILR abscens no stamp of dates in passport

I would appreciate if some one can shed light about how home office confirm abscences if there is no stamp on passport of returning dates in UK. I went to france twice through dover and twice there were only departure dates stamped, no arrival dates stamped.
I am applying at PEO, heard that they tend to ignor all cases were no stamp found. is that right? should I apply by post to save money.
kind regards