Standar spoon arm, two rivot units. The blade is either an 8" or 9" Rainbow "Made in England" unit. (Harder to find)
Nice repops can be had from Healey on ebay. Also Moss has them, arm repops are very close, new blades would just not be stamped.
http://www.ebay.com/itm/MGA-TR2-TR4-...29422a&vxp=mtr
Get park rest to right................