I can't beat your bank's offer, but here's a similar sounding offer. I will now suggest that the bank's interest rate may change and so my offer might look better.
Impressed at his attention to detail - getting my name wrong and confirming my belief that people just make up the rates they tell you, rather than definitely find the best one at any given time, I wrote back in a similar vein:
I have already arranged my mortgage. Tough luck loser.
Actually, I suggested that he get in touch when I start thinking about residential mortgages... you never know. He may pluck out of thin air a rate that I might like.
Being Kevin hasn't been a good thing today.