Don't forget that Brenda and Lillian have 'history'. I would be tempted to manouvre Lillian into saying that covering her work was priority so that I could, in all innocence, leave Matt's work. Then when Matt gets cross I would snitch on Lillian. Meanwhile I would be learning Lillian's role inside out, so I could leave and do it elsewhere. I do so hope that it is Brenda who discovers about the affair and she starts blackmailing Lillian.
I was thinking that Lillian was really off with Brenda actually...in reality this is all preparation for Brenda leaving Ambridge methinks. Tom is a twozzer, he's never going to fit Brenda's hankering for a baby into his business plan, working for Matt n Lillian doesn't give her job satisfaction and she's trained for something much more demanding than covering for her boss while she plays away
It's only a matter of time until she packs her spotted hanky on a stick and heads for the A40.
Also - what a name to be landed with! How old is she? 25? Who on earth is called Brenda who isn't over 40?
I can't believe the way she talks to Lillian, I know Lillian's putting on her a bit but come on! If Lillian doesn't mind there's noone in the office why should Brenda. Brenda's showing her human side a bit more lately but I would be having words if I worked with her.