Why does GB in-app subscription results in 12.17% tax_percentage (VAT) from webhook?

Hi,

We’re seeing events from the Revenue Cat webhook whilst in Sandbox mode (before go-live) where a subscription or renewal flows through with 12.17% `tax_percentage`. Can anyone explain why that might be? I would expect 20% VAT? Is it something we’ve misconfigured or am I missing something?

Example webhook event here:

{
  "api_version": "1.0",
  "event": {
    "aliases": [
      "9e2090e4-11cc-4ff8-8f0f-281eb9e6b84d",
      "$RCAnonymousID:7610af8f52924950b428cd4d313823f2"
    ],
    "app_id": "app790cf74d0c",
    "app_user_id": "9e2090e4-11cc-4ff8-8f0f-281eb9e6b84d",
    "commission_percentage": 0.3,
    "country_code": "GB",
    "currency": "GBP",
    "entitlement_id": null,
    "entitlement_ids": [
      "Pro"
    ],
    "environment": "SANDBOX",
    "event_timestamp_ms": 1678382003118,
    "expiration_at_ms": 1678382162000,
    "id": "6D453662-6B23-47EE-97B4-7856431CA391",
    "is_family_share": false,
    "is_trial_conversion": false,
    "offer_code": null,
    "original_app_user_id": "$RCAnonymousID:7610af8f52924950b428cd4d313823f2",
    "original_transaction_id": "2000000253163431",
    "period_type": "NORMAL",
    "presented_offering_id": "default",
    "price": 11.837,
    "price_in_purchased_currency": 9.99,
    "product_id": "oscil8_umg_staging_1month",
    "purchased_at_ms": 1678381862000,
    "store": "APP_STORE",
    "subscriber_attributes": {
      "$attConsentStatus": {
        "updated_at_ms": 1674161971463,
        "value": "restricted"
      }
    },
    "takehome_percentage": 0.7,
    "tax_percentage": 0.1217,
    "transaction_id": "2000000293715660",
    "type": "RENEWAL"
  }
}

Thanks,

Dan