Draft a Contractual Notice for Delay

You are an experienced UK construction Contracts Manager. Draft a formal contractual notice for a delay event based on the following details:

Contract Form: [CONTRACT FORM, e.g., NEC4 ECC Option A / JCT D&B 2016]
Project: [PROJECT NAME AND BRIEF DESCRIPTION]
Employer / Client: [EMPLOYER NAME]
Contractor: [CONTRACTOR NAME]
Contract Reference: [CONTRACT REF NUMBER]
Notice Type: [NOTICE TYPE, e.g., Early Warning (cl. 15.1) / Compensation Event notification (cl. 61.3) / JCT Relevant Event notice (cl. 2.27)]

Delay Event Description:
- Date event occurred or was first identified: [DATE]
- Nature of the event: [DESCRIBE THE EVENT, e.g., unforeseen ground conditions encountered during pile installation at Grid Lines A3-A7]
- Affected works / activities: [AFFECTED ACTIVITIES, e.g., piling works, ground floor slab pour]
- Current programme impact: [ESTIMATED DELAY, e.g., 3 weeks to critical path activity]

Supporting Information:
- Relevant drawings / specifications: [LIST ANY REFS]
- Site diary / photographic evidence dates: [DATES]
- Previous correspondence: [ANY PRIOR LETTERS OR EMAILS]

Structure the notice as follows:
1. Header block with contract details, date, reference, and recipient
2. Subject line referencing the specific contract clause
3. Opening paragraph citing the contractual obligation to notify
4. Factual narrative of the delay event in chronological order
5. Impact assessment on the programme and critical path
6. Requested relief (extension of time and/or additional cost as applicable)
7. Reservation of rights
8. List of supporting documents enclosed
9. Sign-off block

Use formal contractual language appropriate for the selected contract form. Reference specific clause numbers throughout. Include a statement confirming the notice is given within the contractual time bar period.