Many have aske this question on various cistern lids. showroom/fitters don't keep the covers they only keep and supply the full monty lid and body.
In most case you have to replace the cistern as I've not come across anywhere you can buy just the lid but you can try at your local bathroom store and see if they can order one.
Bob, September 2009
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I can answer this question...
where can I buy a lid for the cistern Shire BS7357/58 model ref 805/815 pc ?