Always been a fan of Currencyfair...until now.
Had two really slow transfers from USD to GBP. Then the latest took so long, after a trace and 8 days it was returned to my bank. The problem appears that Currencyfair now (recently) switched to AIB in Ireland. This is a bailout bank now virtually owned by the Irish government. The service is rubbish.
By contrast, I made the transfer using Transferwise this afternoon. The GBP hit my account about an hour ago! Total elapsed time about 4 hours.
Sorry, Currencyfair your bank needs to be changed for USD transfers.