Posted By Ron Hunter
Sounds on the face of it like a bit of "in-house design" there. I would generally frown on the use of these multi-way blocks in any work - or even home- environment (bever mind a shop floor) as they tend to "stray" into serious socket overload situations. In my workplace, they are prohibited by local rules.
For the kit you describe, and given the work environment, I'd be equally concerned about the suitability of the external cable and socket/cabinet interface that gets the power from the wall to the adaptor block?
There are any number of suppliers who make multi-gang socket outlets (whether IEC or BS 1363) in a robust metal pattern specifically designed for use in 19" racking cabinets. in other words, the design could be way better!

Posted By Peter Still
Gavin,

To respond to your original question, I think the relevant standard would be BS EN 60950 "Information technology equipment - Safety - Part 1 : general requirements". However at £274, and 621 pages, it's a bit of a struggle, and doesn't seem to deal with the situation you describe except in very general terms.
If the equipment within the computer cabinet comes with permanently-attached mains leads, with normal 13A sockets, then they should be fine. If the mains leads are the removable IEC "kettle lead" type then I'd consider replacing them with the type having the IEC male plug at one end and female at the other, and use a multiway IEC adaptor with the appropriate fusing. Both the adaptor and the leads plugged into it should be fixed within the cabinet and protected from any foreseeable damage.
Whether the IEC or BS 1363 type, the multiway adaptor should be a respectable make rather than the "Sunday market special".