Try this
<b>Sheet</b><br /><br /><table border="1" cellspacing="0" style="font-family:Calibri,Arial; font-size:11pt; background-color:#ffffff; "> <colgroup><col style="font-weight:bold; width:30px; " /><col style="width:103px;" /><col style="width:103px;" /><col style="width:103px;" /><col style="width:103px;" /><col style="width:103px;" /></colgroup><tr style="background-color:#cacaca; text-align:center; font-weight:bold; font-size:8pt; "><td > </td><td >A</td><td >B</td><td >C</td><td >D</td><td >E</td></tr><tr style="height:18px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >1</td><td style="background-color:#ffff00; ">Animal Name</td><td style="background-color:#ffff00; ">Animal Type</td><td style="background-color:#ffff00; ">Sex</td><td style="background-color:#ffff00; ">Date</td><td style="background-color:#ffff00; ">Unique Code</td></tr><tr style="height:18px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >2</td><td >cc</td><td >Dog</td><td >Male</td><td style="text-align:right; ">15/01/2019</td><td style="text-align:center; ">DM0119</td></tr><tr style="height:18px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >3</td><td >rr</td><td >Cat</td><td >Female</td><td style="text-align:right; ">28/10/2018</td><td style="text-align:center; ">CF1018</td></tr></table><br /><table style="font-family:Arial; font-size:10pt; border-style: groove ;border-color:#00ff00;background-color:#fffcf9; color:#000000; "><tr><td ><b></b></td></tr><tr><td ><table border = "1" cellspacing="0" cellpadding="2" style="font-family:Arial; font-size:9pt;"><tr style="background-color:#cacaca; font-size:10pt;"><td >Cell</td><td >Formula</td></tr><tr><td >E2</td><td >=LEFT(B2,1)&LEFT(C2,1)&TEXT(D2,"mmyy")</td></tr></table></td></tr></table> <br /><br />