wtd: rear brake disk for steamer

[ram33]

in the middle of rebuilding my bike and noticed the rear disk has at least 2 cracks 
would anyone have a decent brake disk for steamer? maybe someone upgraded their wheels?
im in uk (near derby / notts)
if you can help please pm me
looked around and found a new copy one for £70 which will have to do otherwise

[Geoff W]

Yes £70.00 is about the going rate. My rear caliper tends to stick, and so wears the rear disc. Striping cleaning etc helps alittle but not for long.