Instructions:The latest discount code from T.M. Lewin: 15OFFTML will get you 15% off your online order. "Discount is able to be used on sale items" and is not limited to the current sale on shirts.
Of course, you can combine it with "4 from £80" on shirts if you either a) buy 5 shirts for £120, or like be b) buy the more premium / fitted cuts which are 4 for £120 anyway.
Or just enjoy 15% off a new suit for 2015 :)
Discount applies in-store too: you can wave this barcode at them at the till and it will apply the discount.
Potentially Quidco or TCB too