Address lookup is lightweight.
Property data is the product.

Request

# Step 1 — Address search (2 calls)
curl https://api.homedata.co.uk/api/address/find/ \
  -G --data-urlencode "q=10 Downing Street, London"

# Step 2 — Full property retrieve (5 calls)
curl https://api.homedata.co.uk/api/address/retrieve/10002210501/ \
  -H "Authorization: Api-Key YOUR_KEY" \
  -G --data-urlencode "level=full"

import requests

API_KEY = "YOUR_KEY"
BASE    = "https://api.homedata.co.uk"

# Step 1 — Address search (2 calls)
res  = requests.get(f"{BASE}/api/address/find/",
       params={"q": "10 Downing Street, London"})
uprn = res.json()["suggestions"][0]["uprn"]

# Step 2 — Full property retrieve (5 calls)
prop = requests.get(f"{BASE}/api/address/retrieve/{uprn}/",
       headers={"Authorization": f"Api-Key {API_KEY}"},
       params={"level": "full"})
print(prop.json())

const BASE    = "https://api.homedata.co.uk";
const API_KEY = "YOUR_KEY";

// Step 1 — Address search (2 calls)
const find = await fetch(
  `${BASE}/api/address/find/?q=10+Downing+Street+London`
);
const { suggestions } = await find.json();
const uprn = suggestions[0].uprn;

// Step 2 — Full property retrieve (5 calls)
const prop = await fetch(
  `${BASE}/api/address/retrieve/${uprn}/?level=full`,
  { headers: { "Authorization": `Api-Key ${API_KEY}` } }
);
console.log(await prop.json());

Response — property data, not just an address

{
  "uprn": "10002210501",
  "address": "10 Downing Street, London",
  "postcode": "SW1A 2AA",
  "bedrooms": 4,
  "property_type": "Terraced",
  "current_energy_efficiency": 72,
  "epc_floor_area": 310,
  "construction_age_band": "1900-1929",
  "has_garden": false,
  "building_height": 14.2,
  "latitude": 51.5034,
  "longitude": -0.1276
}

Ideal Postcodes would stop after returning the address string. Homedata returns the property too — same API, one more call.