Hi Onno, 
 
Thanks for your question. 
 
We can do our Latex Topper to those measurements. However, please note that as it is a non-standard size there is no standard 60 day love it or return it guarantee on it as we have limited resale ability on those items. 
 

 
Similarly, there would also be an additional 10% charge on the cost of a standard King Size as we would be increasing the length by 6". 
 
The price here, inclusive of the additional fee, would be £489.50 (October 2018).
 
I hope this has answered your questions fully but if you do have any further queries please don't hesitate to contact our office on 0161 437 4419.
 
Kind Regards, Lee.