TM Lewin are running their frequently repeated 4 shirts for £80.
But currently, Quidco are offering a massive 20% off, making the 4 shirts £64, or £16 per shirt (quidco rate until midnight 12.7.2014)
£3.95 delivery, or free delivery to store
Code "TMLSALE6" will give you FREE delivery to home, but Quidco may drop their rate from 20% to 7%, so not really worth the risk.
Personally, I prefer TM Lewin to Charles Tyrwhitt. Many will disagree.