£51 from
Alfa Workshhop. Doesn't say which one it's for (oh yeah it does, front again), but worth giving them a bell and asking.
You could try EB Spares as well.
Just had a look
here. Doesn't look good. That does seem ridiculous though.
Although my V6 has ABS and it definitely did not cost anything like £260 for it. I think you're gonna have to call someone about it.