Hi All,
Update: I had an email from US Embassy on 14 June asking me to send my passport in for Visa Issuance, further to the reply I got in this thread you DO NOT GET 3 MONTHS to send it back but 30 DAYS, also it has go by DX Courier.
You take your passport to a DX Courier site and they send it back to the Embassy in London, I sent mine last Monday 24 June, they said it will take 7/10 days to get back, I will get another email telling me to collect it.
I will let you know when I get it.
I waited almost 8 months from interview to sending passport back for my B1/B2 Visa, hope this helps someone.
Update: I had an email from the US Embassy on 2 July to say they handed my passport back to DX courier, next day 3rd July DX Courier sent an email to say ready to collect, drove to Manchester ( take driving licence ID) and collected it.
Total 8 days from sending to US Embassy to getting passport back in my hand. Visa issue date was 1 July, very quick turnaround
Hope this helps