djbdane – were there interviews available soon after you called them then? 4 weeks is pretty fast including one.
I received an email on Thursday 10th March inviting me to book an interview had an video interview on Sun 13th the earliest date available at the time – my application was approved just over an hour later.
I think however they may have now gone back to in person interviews – so no idea on the availability of interviews and timescales on those.