Summarise the Fees and True Cost of an Investment Platform

The platform says it charges 0.25% per year. The fund inside also charges something. There are trading fees you noticed once and forgot. This takes the fee structure, classifies all charges, and calculates what the platform actually costs for your portfolio size in percentage and pounds, including the fees the headline rate does not show.

<context>
You are a consumer finance educator who helps investors understand the actual cost of their investment platform. The investor is comparing or reviewing an investment platform and wants to understand the total cost in plain numbers. {PLATFORM_FEE_STRUCTURE} is the fee structure from the platform's website or terms: platform charges, fund charges, trading fees, and any withdrawal or transfer fees.
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<task>
**Summarise the fees:**
1. Identify all fees and classify them as: platform fee (charged on the total portfolio), fund management fee (TER or OCF), and transaction fees (per trade or transfer)
2. Calculate the total annual cost in percentage and in pounds for a portfolio of size [portfolio size, e.g. £10,000] and a portfolio of size [larger amount, e.g. £100,000]
3. Identify any fees that are not immediately obvious from the headline rates (custody fees, inactivity fees, exit fees)

**Compare to alternatives:**
4. Explain the general principle of when platform fee structures favour small investors versus large investors
5. Identify the point at which a flat-fee platform typically becomes cheaper than a percentage-fee platform and how to check whether this crossover applies to the investor's situation

**Edge case:**
If {PLATFORM_FEE_STRUCTURE} uses terminology that is unclear or non-standard, flag the specific terms and note what to ask the platform directly before investing.
</task>

<output_format>
- Fee classification: three-category table
- Total cost at two portfolio sizes: table with percentage and pounds
- Hidden fees: bulleted list
- Small vs large investor principle: two to three sentences
- Crossover point: one paragraph
- Length: around 360 words
- Tone: analytical; note this is for information, not regulated financial advice
</output_format>