Checkout Attributes displaying with %20 & %2520 & %252520 in the invoice PDF and order page

Can't narrow down the cause, but we have lots of these coming though when the checkout attribute using textbox for delivery instructions is completed.

i.e.
Catalogue Request: Yes<br />Delivery Instructions: Please%20deliver%20on%20Friday%201%20March%2C%20and%20please%20knock%20door%20knocker%2C%20and%20allow%20time%20for%20me%20to%20come%20downstairs.

and xml stored like this
<Attributes><CheckoutAttribute ID="1"><CheckoutAttributeValue><Value>1</Value></CheckoutAttributeValue></CheckoutAttribute><CheckoutAttribute ID="2"><CheckoutAttributeValue><Value>Please%20deliver%20on%20Friday%201%20March%2C%20and%20please%20knock%20door%20knocker%2C%20and%20allow%20time%20for%20me%20to%20come%20downstairs.</Value></CheckoutAttributeValue></CheckoutAttribute></Attributes>

Might be users on IE, but can't be sure.
Any ideas why this might be happening and how to stop it.

Thanks
M@

This is for V4.1

How do you get that into the email?