Were either the claimant's application for payment or the subsequent certificate issued by the engineer valid?
Links
[1] https://www.fenwickelliott.com/sites/default/files/Legal%20Briefing%2046-2008.pdf
[2] https://www.fenwickelliott.com/sites/default/files/Legal%20Briefing%2042-2008.pdf
[3] https://www.fenwickelliott.com/sites/default/files/Legal%20Briefing%2040-2008.pdf
[4] https://www.fenwickelliott.com/sites/default/files/Legal%20Briefing%2038-2008.pdf
[5] https://www.fenwickelliott.com/sites/default/files/Legal%20Briefing%2030-2008.pdf
[6] https://www.fenwickelliott.com/print/research-insight/newsletters/legal-briefing/adr-arbitration-litigation?page=15