Fox's Glacier Mints ran a Rapide (G-AIDL) out of Leicester for many years in the 50s/60s, alongside the English Electric Heron flown by Alan Firmin. Alan had his own Decca approach to cope with the inadequacies of Leicester East ! The Heron had a regular schedule to Valley to cover the construction of an early nuclear power station on Anglesey. (Wyddfa ?)
I also remember first a Beagle 206 then an Aztec, owned by Associated Tobaccos which operated for a few years until it was, I think, written off during an asymmetric refresher.
A long time ago so could be slightly wrong on a couple of aspects.