Readme update
Readme update

TARIC & CHIEF capitalisation, minor language tweaks

alphagov/trade-tariff-backend,leftees/trade-tariff-backend,leftees/trade-tariff-backend,bitzesty/trade-tariff-backend,bitzesty/trade-tariff-backend,alphagov/trade-tariff-backend,bitzesty/trade-tariff-backend,alphagov/trade-tariff-backend,leftees/trade-tariff-backend