Strange Valentine tank markings

Living History

Hi guys

Does anybody have any idea what this marking is ‘Exp School LUL’ on this Valentine MkXI?

My guess is Experimental School Lulworth, a wing inside The Armoured Fighting Vehicle School Lulworth maybe?

Any idea of a date? When were the MkXI trialled?

IMG_0421_zpsfe4c860c.jpg

Smudge

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