The trust deed will stay on your credit record for 6 years from the date that you took out the trust deed, it should be removed automatically after the Sixth anniversary.
After your Trust Deed has finished usually Three years, it will remain on your credit record for three more years (Six in total), although this may show as settled after Three years, it would make it more difficult (but not impossible) to obtain credit. If you have a completion certificate from the I.P..... then any photocopies sent onto the credit agencies will allow your records to be amended and marked as settled.