No start, Help?

[TSP]

All,
My car is a 1997 986. We’ve had it for quite a few years and it has always been very dependable. Lately, it will sometimes fail to start. Turn the key and all the dash lights up, I can hear the fuel pump spin up but turning the key does nothing. I’ve read here and elsewhere and have replaced a few bits, mainly because it is coming up on 100,000 miles and I figured can’t hurt. The starter was replaced when the clutch and IMS were done a few weeks ago, I replaced the ignition switch and the micro switch on the clutch. Both keys have new 2032 batteries. The car battery was replaced last year. I took it to a reputable shop (no names to protect the innocent) and they thought it was sorted (starter replaced at time of clutch/IMS), but today, it did it again. What else could this be? I’m a decent backyard wrench, but not an electrician. Any ideas at all?
Thanks
T