Have a read here:
https://www.iva.co.uk/what-does-an-iva- ... dit-record
When you were sent the certificate, a copy should have been sent, by your IP, to the Insolvency Service. It will take them "up to" three months to remove you from the register. Once you are off the register the credit reference agencies will remove the IVA once the 6th anniversary has passed. It is certainly worth contacting the CRAs with a copy of your completion paperwork as soon as possible, in case they are moved to act sooner.
In 10 years on this forum I have only seen the insolvency service act faster a few times --- despite being told otherwise it seems that they wait until the three months is up, to the day. That said, this forum, and others like it, usually only get the bad side of any story !
On the mortgage front, a good broker will help you with the credit clean up, prior to you making an application. There are two, who post on this forum, with experience in adverse credit applications: Ryan and Shaun. They both have lenders who are more sympathetic to those of us with an IVA in pour past.
Contact details can be gleaned from their profiles:
Ryan:
https://www.iva.co.uk/forum/memberlist. ... le&u=18488
Shaun:
https://www.iva.co.uk/forum/memberlist. ... le&u=22837
I am not qualified to give advice and can only state my opinions, based on my IVA experiences.