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How to Write a Website RFP Brief in London in 2026

Mohamed Bah·Fondateur, Kolonell
September 15, 2026
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How to Write a Website RFP Brief in London in 2026

How to Write a Website RFP Brief in London in 2026

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The verdict in three sentences

An effective B2B website RFP brief in 2026 fits into 12 sections and turns vague wishes into 20 to 40 quantified, testable requirements. This document sets a realistic budget of GBP 15,000-60,000 and prevents change requests that inflate costs by 30-50 %. Without a weighted scorecard, the consultation becomes a beauty contest instead of a rational choice.

The 12 essential sections of an RFP

An incomplete brief is the number-one cause of overruns. Every missing section becomes a grey zone where the vendor sets its own rules, usually billed mid-project. Here is the expected 2026 backbone and the risk of skimping on each section.

RFP sectionExpected contentCommon mistake
1. Context & goalsAudiences, KPIs, indicative budgetNon-measurable objectives
2. Functional scopePrioritised feature listOpen scope, no MoSCoW
3. Sitemap & contentPage count, who writes contentContent "to be supplied later"
4. Technical requirementsCMS, hosting, performance, SEOStack imposed without reason
5. Design & UXGuidelines, references, a11y"Wow us" with no framing
6. IntegrationsCRM, ERP, marketing automationForgotten third-party APIs
7. Legal constraintsGDPR, notices, accessibilityHandled at the very end
8. Timeline & milestonesKey dates, dependenciesUnrealistic imposed deadline
9. Budget & termsRange, milestone paymentsHidden budget = padded quotes
10. Selection criteriaWeighted scorecardGut-feeling choice
11. UAT & warrantyAcceptance criteria, warrantyUndefined sign-off
12. Support & exitMaintenance, code ownershipVendor lock-in

Quantify requirements and score vendors

An unquantified requirement is not a requirement. "The site must be fast" is worthless; "every page loads in under 2 seconds on 4G, Lighthouse score > 90" is enforceable. Aim for 20 to 40 quantified requirements split into Must, Should and Could. On selection, a weighted scorecard makes the decision objective and protects the buyer against internal challenges.

Selection criterionWeightWhat is scored
Understanding of need25 %Reframing, relevant questions
Comparable B2B references25 %3 similar quantified cases
Technical & SEO solution20 %Stack, performance, a11y
Team & methodology15 %Profiles, sprints, governance
Price & terms15 %Value/price ratio, milestones
Total100 %Score out of 100 per bidder

The consultation runs 3 to 4 weeks: 1 week to issue, 1-2 weeks to respond, 1 week to analyse and hold pitches. Any shorter and you get rushed quotes; any longer and your best candidates disengage.

Mini case study

Helen, marketing lead at an 80-person industrial SME in London, wants to redesign her B2B site. With no brief, her first vendor call yields a "from GBP 12,000" quote that is impossible to compare. She writes a 12-section RFP with 28 quantified requirements, then invites 4 agencies using her weighted scorecard.

Result: incoming quotes range from GBP 19,000 to 34,000 for a finally identical scope. She picks the GBP 24,000 offer scored 82/100 over a GBP 19,000 offer scored 61/100 (no content, no warranty). By locking the scope, she avoided an estimated GBP 8,000 change request on content and SEO, or 33 % of budget.

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FAQ

How long does a good RFP take to write?

Allow 3 to 5 days of effective work spread over 2-3 weeks, including internal interviews. A B2B website brief typically runs 15 to 30 pages. It is an investment that cuts change-request risk by 30-50 %.

Should the budget be stated in the brief?

Yes, a range (for example GBP 20,000-30,000). Hiding the budget produces misaligned quotes and doubles analysis time. A range lets vendors calibrate without underselling value.

How many vendors should I invite?

Three to five maximum. Fewer means no real comparison; more makes analysis unmanageable and the best drop out, judging their odds too low.

Does an RFP really stop overruns?

It does not eliminate them but divides them. On our projects a quantified brief cuts the change-request rate from 30-50 % to under 10 %, because every change becomes a measurable deviation from the agreed scope.

Who should sign off the brief internally?

The sponsor (leadership), the business (marketing/sales), IT and, where relevant, legal for GDPR. Without cross sign-off you discover blocking requirements mid-development.

Let's scope your project. Send us your brief or objectives (scope, indicative budget GBP 15,000-60,000, target timeline) and we will reply with a clear reading grid. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.

Tags:#cahier des charges#site web B2B#appel offres#exigences#selection prestataire#methodologie
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Mohamed Bah

Fondateur, Kolonell

Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.