Leasehold Deed Variation Drafting

I have a deed of variation already made. Need checking for wording so that it complies with current UK conveyancing practice, satisfies my lender Halifax's requirements. I am the shared freeholder so no premium is payable. Other freeholder completed lease extension some years back to set to 999 years. Doing the same to align.

Key information
• Property type: residential leasehold
• Specific service: deed of variation (rather than a full sale / purchase)
• Primary objective: extend the lease term

Deliverables
1. Draft deed of variation, ready for signature by all parties
2. Obtain approval from Halifax/Lloyds through portal. You need to be on their list of approved solicitor or conveyancer.
3.Land Registry submission

Acceptance criteria
• Draft reflects the existing lease clauses, adding the new term length without altering rights or covenants unless expressly agreed.
• Formatting matches Land Registry deed standards (font, margins, execution blocks).
• Any lender-specific wording is incorporated where relevant.
• Turnaround: first draft within 5 working days of receiving the current lease and title documents.

I already hold a scanned copy of the existing lease and the latest official copy of the register, which I will forward on engagement.