I wouldn't worry too much about it. The point is that you're developing for the LAMP platform.

OK, so your expertise is mostly in the 'p' and 'm' parts, but as long as you're not advertising yourself as a Linux sysadmin or an Apache specialist, I'd say that's ok.

Bearing in mind that most recruitment agencies don't have the slightest idea what any of this means anyway... and if you're in an interview with an actual employer then you'll be able to discuss exactly where your experience lies.