Okay, so this is how I imagine this conversation went:

Asda Employee:  
'Hello 'dis Asda, how can I help you?'

 
Customer:
' I would like to order a cake for a
leaving party this week.'

Asda Employee:  
'What you want on 'da cake?'

Customer:
'Best Wishes Suzanne' and
underneath that 'We will miss you'.