Build a messaging framework

I work in marketing at an accountancy firm. Help me build a simple messaging framework for the firm.

Context: Partners describe the firm by service line: audit, tax, accounts, payroll. Clients describe it by what they get, which is usually peace of mind about deadlines and a person to ask.

Before you start, ask me for anything missing from this list:
- Who we help
- What we do and how it differs
- Proof for each claim

Then:
1. Write one sentence that says who we help and how.
2. Add three supporting messages with proof.
3. List phrases to use and to avoid.

Give me:
- A one-page framework
- A 25-word and a 50-word description of the firm

Rules:
- Use only the facts I give you. Where something is missing, write [detail needed]. Never invent a number, a name, a quote or a source.
- Give general information only. Never write anything that reads as tax advice on a person's own affairs, and never suggest a tax saving or an outcome with HMRC is likely or guaranteed.
- Write in plain English, in our voice if I have given you a sample.
- Do not tell me what the rules or regulations say. If something may be restricted, flag it and I will check.

Finish with a list headed "Check before this goes out". Include these, plus anything else the partner who approves marketing or our ethics and compliance lead should see:
- Proof behind each claim, especially on savings and response times
- Use of chartered, certified, specialist and proactive
- Partner agreement before the framework is used