‘Becky,’ she greets me in her low, well-modulated voice. ‘How lovely to see you. I’ve ordered some sparkling water …’

‘Fab!’ I beam at her. ‘And thanks so much for helping out.’

‘Oh, it’s no trouble. Now, let me show you what I’ve done so far.’

She pulls out a plastic folder and starts fanning printed papers across the table. ‘Guests … contacts … dietary requirements …’

I goggle at the pages in amazement. Luke’s right, Bonnie’s awesome. She’s compiled a full list of guests from Luke’s business and personal address books, complete with addresses, phone numbers and a little paragraph on who each person is.

‘Everyone in the company has blocked off the evening of 7 April,’ she continues. ‘I’ve taken Gary into my confidence, and we’ve invented a full company training session. Here you are …’

Speechlessly, I look at the sheet of paper she proffers. It’s a schedule for a ‘Brandon Communications Training Session’, beginning at 5 p.m. and lasting into the evening with ‘drinks’ and ‘group activities’ and ‘discussion circles’. It looks so genuine! There’s even the name of some ‘facilitating company’ printed at the bottom.

‘This is brilliant,’ I say at last. ‘Absolutely fantastic. Bonnie, thank you so, so much—’

‘Well, it means you don’t have to tell anyone at the company the truth just yet.’ She gives a little smile. ‘These things are better kept under wraps for as long as possible.’

‘Absolutely,’ I agree fervently. ‘The fewer people who are in on the secret, the better. I’ve got a list of exactly who knows and it’s tightly controlled.’

‘You seem to have things very well in hand.’ She smiles encouragingly. ‘And how are the party arrangements themselves going?’

‘Really well,’ I say at once. ‘I mean … I haven’t quite finalized everything …’

‘Have you thought about employing a party planner?’ enquires Bonnie mildly. ‘Or one of the concierge services? There’s one in particular that several of my employers have used, called The Service. Very efficient, I can recommend them.’

She takes out a notepad and scribbles down a number. ‘I’m sure they’d help with organizing, sourcing, providing staff, whatever you need. But it’s just a suggestion.’

‘Thanks!’ I take the paper and put it in my purse. That might not be a bad idea, actually. I mean, not that I need any help. But just to tie up any loose ends.

The waiter arrives, and we both order salads, and he refreshes our water. As Bonnie sips meticulously, I can’t help eyeing her with curiosity. If you think about it, this is the Other Woman in Luke’s life. (Not in a Camilla Parker-Bowles kind of way. Definitely not. I’m not falling into that trap again of thinking Luke’s having an affair and hiring private detectives and getting myself all stressed out over nothing.)

‘Did you want some wine, Becky?’ says Bonnie suddenly. ‘I have to remain professional, I’m afraid …’ She gives a regretful smile.

‘Me too,’ I nod, still fixated by Bonnie.

She spends more time with Luke than I do. She knows all about huge areas of his life that he never bothers telling me about. She probably has all sorts of interesting insights on him.

‘So … what’s Luke like as a boss?’ I can’t resist asking.

‘He’s admirable.’ She smiles and takes a piece of bread from the basket.

Admirable. That’s so typical. Discreet, bland, tells me nothing.

‘How is he admirable, exactly?’

Bonnie gives me a strange look, and I suddenly realize I sound as if I’m fishing for compliments.

‘Anyway, he can’t be Mr Perfect,’ I add hurriedly. ‘There must be things he does that annoy you.’

‘I wouldn’t say that.’ She gives another closed smile and sips her water.

Is she going to bat away every question like that? I suddenly feel an urge to get underneath her professional veneer. Maybe I could bribe her with a hazelnut chocolate.

‘Come on, Bonnie!’ I persist. ‘There must be something that annoys you about Luke. Like, I get annoyed when he answers the BlackBerry all the time in the middle of conversations.’

‘Really.’ Bonnie gives a guarded laugh. ‘I couldn’t say.’

‘Yes you could!’ I lean across the table. ‘Bonnie, I know you’re a professional, and I respect that. And so am I. But this is off the record. We can be honest with each other. I’m not leaving this restaurant till you tell me something that annoys you about him.’