Andy wrote:

My problem is that I am worried about how I tie 4" medium density blocks
into brickwork, worse, preexisting brickwork. How do you tie a block wall
into a two-brick
pier? I see these galvanised mesh ties exist but surely they're only good
for new work. Is it practical to rake out old mortar and shove one end of a
mesh tie into prexisting
brickwork?

I'm thinking there may be something I can screw into the existing pier, then
cement into the block work, but the only things I've seen look like cavity
wall ties.

You need these babies: http://tinyurl.com/8zag2 (or
http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=101892&ts=73501&id=31633)

David