Currently in the process of switching to Avant, and found them to be very 'nitpicky' about everything too.
First contacted broker in mid-Jan, got loan offer on March 1st. That day the broker contacted me to tell me to contact the solicitor to arrange to sign documents. I contacted them and was told that it would be a couple of days before they had everything from Avant and that they'd contact me once they had it. I haven't heard from them since.
I did receive a printed copy of the loan offer in the post myself on March 2nd, so I'm sure the solicitor must have received it that week too. Does anyone know how long it usually takes for a solicitor to do this? I don't want to be a pest contacting them about it if this is normal, but would also like to get it done and dusted.