pistons and new rings for the austin/morris are super cheap..... the pistons etc are the same as in Mini's,Austin Marina's,Morris Minor's and MG's... all you need to do is check it is an A series Block...and order the right size/set..explain to them and theyll sort you out..Real nice guys..
My gals ride is an Austin truck that had an A series in it...i got stuff to freshen up that real easy... i have a contact in the Uk that will ship them anywhere or i can get one of my friends in that locale to pick em up n ship to ya..
heres the shop link... http://www.morrisminor.co.uk/index.htm

they specialise in MG,Morris and Austin Spares, aswell as Jag n other brit car marques...
hope this is a help...