Has my return been processed ?

You will receive an email to confirm if your return has been processed, whether it is a refund or replacement. 

Returns are normally processed within 24 hrs of receipt, if you have not received an email to confirm processing of the return, we have either not processed it or not received it. 

Please check when you sent the item(s) back to us and allow a reasonable amount of time in addition to our processing time before contacting us.

As per this message in our returns information, you should be able to check tracking or proof of posting dates:
We advise that valuable goods are insured, sent on a "signed for" service (refunded on faulty products). Lower value goods - request a proof of posting from your carrier.