that was quite interesting

I decided to look up more info on wikipedia and apparently the machines running this service cost about £200,000 each!

https://en.wikipedia.org/wiki/Prestel

Prestel computers were based on GEC 4000 series minicomputer with small differences in the accumulation according to the function of the machine

Although technically categorised as minicomputers, these GEC machines were physically very large by today's standards, each occupying several standard communications cabinets, each standing 6-foot (1.8 m) high by 2 feet (0.61 m) wide. The CDC 9762 hard disc drives were housed separately in large stand-alone units, each one about the size of a domestic washing machine. (See images in the photo of the GEC Computers' Development Centre). The 70 Mbyte capacity hard discs themselves were in fact removable units, each consisting of a stack of five 14-inch platters, standing 4 inches (10 cm) high, that could be lifted in and out of the drive unit.

The GEC machines cost in excess of £200,000 each at GEC standard prices