“In general Part 8 proceedings are wholly unsuitable for the trial of an issue of estoppel. Once such a claim is disputed, save in exceptional cases, the proceedings will cease to comply withCPR r 8.1 (2)(a), since they will cease to be proceedings in which the parties do not seek the court’s decision only on questions which are unlikely to involve a substantial dispute of fact. A disputed claim of estoppel should be carefully pleaded.”
“10A. The 2022-23 Payments Schedule: (a) Was an instruction given by VCL under, and not a variation to the Subcontract. (b) Had therefore to be read subject to the Subcontract, and in particular subject to clause 4 of the Subcontract. (c) Did not set out a clear and transparent regime setting out what sums became due and when for the purposes of clause 4 of the Subcontract. In particular, the 2022-23 Payments Schedule did not set out any (alternatively any clear and unambiguous) Interim Valuation Dates for the purposes of continuing the interim payment regime beyond the dates set out in Numbered Document 6 to the Subcontract, meaning that theScheme for Construction Contracts (England & Wales) Regulations 1998 (SI 649/1998) applied to fix the relevant (valuation) periods instead. That in turn meant that (so long as the 2022-23 Payments Schedule applied) there was no relevant right under the Subcontract to submit a contractually-compliant application pursuant to clause 4.6.3.1 as had otherwise been the case; (d) Alternatively, contemplated Gypcraft’s interim payment applications were to be submitted on the interim valuation date, and not 4 days in advance of it, meaning that any applications submitted in accordance with the 2022-23 Payments Schedule would not be submitted in accordance with the Subcontract; (e) Therefore on either basis the Subcontract at all material times (whether as amended, varied or supplemented by the 2022-23 Schedule) was not (or was no longer) a contract which required or permitted Gypcraft to submit an application within the meaning ofs110B (4) of the Housing Grants, Construction & Regeneration Act 1996 .”
“the courts expect the parties to adopt business common sense as to the arrangements for invoicing and payment.”
“(d) The estoppel by convention referred to above is found in, and/or arose by reason of the parties communications across the line, objectively construed, as found in the interim payment applications, the payment notices, and the invoices (including for the avoidance of doubt the subsequent interim payment applications) in which Gypcraft represented to VCL that the net summary position as at the start of that payment cycle was to be found only in the gross value of the work done less the amounts invoiced by Gypcraft in accordance with the previous payment cycles. In particular, by those representations Gypcraft impliedly represented there were no other notified but uninvoiced sums which had to be taken into account when assessing movement in the month (i.e. since the time of the last valuation). VCL relied on that convention when it took up, assessed and valued Gypcraft’s applications submitted on that basis, such that it would be unconscionable for Gypcraft to withdraw from that convention with retrospective effect and for Gypcraft to claim payment of its interim payment application 23 on the basis that that sum has self executed in the amount claimed.”
“(a) An estoppel by convention can arise when parties to a contract act on an assumed state of facts or law. A concluded agreement is not required but a concluded agreement can be a ‘convention’. (b) The assumption must be shared by them or at least it must be an assumption made by one party and acquiesced in by the other. The assumption must be communicated between the parties in question. (c) At least the party claiming the benefit of the convention must have relied upon the common assumption, albeit it will almost invariably the case that both parties will have relied upon it. There is nothing prescriptive in the use of ‘reliance’ in this context: acting upon or being influenced by would do equally well. (d) A key element of an effective estoppel by convention will be unconscionability or unjustness on the part of the person said to be estopped to assert the true legal or factual position. I am not convinced that ‘detrimental reliance’ represents an exhaustive or limiting requirement of estoppel by convention although it will almost invariably be the case that where there is detrimental reliance by the party claiming the benefit of the convention it will be unconscionable and unjust on the other party to seek to go behind the convention. In my view, it is enough that the party claiming benefit of the convention has been materially influenced by the convention; in that context, Goff J at first instance in the Texas Bank case described that this is what is needed and Lord Denning talks in these terms.”
“In my view, that general guidance applies equally to a payment notice and a pay less notice. Each has to make plain that it is, respectively, a payment notice or a pay less notice. Each has to clearly set out the sum which is said to be due and/or to be deducted, and the basis on which that sum is calculated. Beyond that, the question of whether or not it is a valid notice in accordance with the contract is a matter of fact and degree.”