Interview at 20 weeks pregnant

[EBM20]

I lost my job due to coronavirus. I have been crazy applying for jobs and finally today I had a phonecall interview for a sales company. I have made it through to the next stage and been invited in for a face to face interview next week.

I'm starting to get a bump and my black trousers will not do up! Anyone know where to get maternity work wear/ smart clothes that will hide the bump?

Also at what point do I tell them I'm pregnant? At the interview? Once they have offered me the job? Or once I have started? I legally have 4/5 weeks until I have to tell them