In fact, this is a misattribution. The symphony from these YouTube videos is not Cuclin's Symphony No. 7, but his Symphony No. 17 "In preclassical forms" from 1965. I once got a broadcast recording of this symphony (again, just three movements, by the way) plus announcement which definitely clarified things. The title partly explains the neoclassical formulas Cuclin uses in this work (which, to be honest, I am not too fond of).