Loading Acorn (BBC) sideways RAM.

This is a really trivial question, but I wasn't really a BBC micro hacker in the old days, I am planning some upgrdes to a BBC Model B+ (the fact that this particular B+ lives in the bottom of an Acorn Cambridge shouldn't matter...). One of them is to combine some of the ROMs (the B+ can take 27256 32K byte EPROMs), thus freeing up some ROM sockets and put a RAM chip in one of them. I then have to fiddle the write-enable line [1] (should be easy) and I have 32K of sideways RAM. The hardware doens't worry me (I have schematics...). But how do I load a ROM image into the sideways RAM? Is there some loader program I need (and where do I get it)? Anything I should know about the image file on disk (anything about the start/end/entry addreeses in the direxctory, for example)? [1] I believe it's a good idea to be able to write-protect the sideways RAM, but I don't want to drill holes in my Cambridge. Has anoyne ever used the cassette motor line for this? Seems like an obvious thing to use. -tony