Willden Services Ltd were based in Crowborough, East Sussex and appear to have just published the one program for the Sinclair QL home computer, QL Paymaster, a payroll program.
It could be that the name of this company was a printing error, as there is a Wilden Services Limited based in Hemel Hempstead who have been in existence since 1973, but they deal in "Plumbing, heat and air-conditioning installation". There is no sign of a company called Willden Services Limited on Companies House.