Thanks Elvin,
Yes indeed, it's the ecu for the abs/tc, Bloody awkward to remove, ordered an identical 'used but guaranteed' part off ebay for 30 quid, i'll wait till it arrives (and the rain stops) before i switch them over.
at which time I shall renew all the brake fluid throughout and check the integrity of the abs senders.
Your link has been extremely helpful.
Just an additional note: I had originally dismissed the ecu, as my speedo is fine, i had thought that speedo failure was necessary to proove ecu fault.. It's not!
Cheers!