Fuel Injection?

Hi - We have a Ford Fiesta 1.4 Ghia (1.4) Diesel (55 plate) which for a while now has had the EAC Fail light on. Had it in the garage and they have replaced the wiring but still not cured the fault (sorry for the untechnical question but know nothing about cars!). They sent it to a 'specialist' garage (not Ford) and have quoted me £1400 to replace all 4 fuel injectors, quoting £300 each for the injectors. Am I being ripped off! PS. Already cost £200 for the wiring.