The registration page for Lumia 625 is up at both CarphoneWarehouse and Phones4u in UK. The coming soon page at CPW mentions September availability for the device.
According to the UK press release sent to us by Nokia,
Lumia 625 will come with an estimated retail price of £200 before taxes and subsidies and will begin selling in the UK in Q3. At launch in the UK, the Nokia Lumia 625 will be available from Vodafone, O2, EE, Carphone Warehouse and Phones4u.
So, seems September may be the time when we will see both Lumia 1020 and Lumia 625 coming to UK.