Hi again,
the cost of exams in UK quoted at http://www.comptia-certification.co.uk/exams.html are
CompTIA A+ (2 exams) £111+VAT
CompTIA Network+ £164+VAT
CompTIA Security+ £179+VAT
one locator for exams is http://www.pearsonvue.com/comptia/locate/
and the results for UK show test centers are in most cities
regards