"The theory (as I would have it) of evolution and the subsequent theory of natural selection are undoubtedly the best explanations we have of the diversity and complexity of life that we see around us. They are probably the best explanations we will ever have."

Agreed, except that "the theory of evolution" is actually "the theory of evolution by natural selection." I agree with "probably." The beauty of science is that "probably" is as good as it ever gets. Other areas of human endeavour that espouse unwarranted certainty can be so ugly in comparison, in the ways they entrap millions of people.

"My objection is to either or both of them being referred to as "True" which converts them into a quasi-religious belief system and removes them from science."

Well I also object to theories being called true. Unfortunately, you are still refusing to understand my point about evolution being an incontrovertible natural phenomenon. That's the starting point for scientific investigation, and the scientific investigation of evolution has been one of the greatest triumphs of humanity. In stark contrast, religious belief systems, quasi or not, can't be subjected to the scientific process because they all start with a premise that has deliberately been put beyond rational investigation. To claim that my statement that "evolution is true" is putting it on a quasi-religious footing is patently ridiculous, and places you precisely and fully in pete's camp.