Not seen one of these but they sound interesting. Beebug vol 4, issue 9, page 6, News section says:
"The Spider interface is a boon for computer control enthusiasts. Combining both sideways RAM and ROM software, the Spider board provides a set of process timers and practical real time input/output software tools. The budget Spider uses the Printer and User ports and costs £65. More extravagant web spinners can use the 1MHz bus with the £115 Spider. Further details from the manufacturer, Paul Fray Ltd on 0223-66529."