Get 3 statutory credit reports from Experian, Equifax and Call Credit - Cost £2 each, sign up to noddle.co.uk (it's free and part of call credit if you like) Experian and Equifax also offer free trials but will charge you after the trial if you don't cancel.
Check to ensure the IVA is marked as completed, if it is not the first thing to do is write to the relevant Credit Reference Agency (CRA) enclosing a copy of your completion certificate and asking them to mark it as completed.
I'm also assuming you've already checked the insolvency register to ensure your details have been removed.
Next check for any Defaults on your file. If there are any make sure they are marked as Satisfied, show a outstanding balance of zero and the default date is on or before the start date of your IVA.
Hopefully your bank has been reporting positive data at the CRA whilst you were in your IVA along with other companies, e.g. a mobile or broadband provider.
It sounds strange but get yourself a credit card, you can either wait like I did until the 6 year point (Barclaycard are likely to accept

if they were not a previous creditor

) or go to somewhere like Vanquis once you've cleaned your file up for improved chances of acceptance there.
MAKE SURE YOU PAY THE CREDIT CARD IN FULL EACH MONTH WITHOUT FAIL. Vanquis will charge a high rate of interest if you don't, and you really don't want to fall back into the same pre-iva trap most of us fell into before with borrowing again. Think of this as a Credit Repair Exercise in order to get a mortgage.
Finally when applying for a mortgage, I understand that Building Societies look more favourably on people in previous IVA's but they do look for the IVA to have been settled for anywhere between 1 and 6 years, some will never look at a previous BR or IVA regardless of timeframe. Considering we actually own these banks the government should really do something as this is unfair, and someone in a IVA is forever going to be penalised with higher interest rate charges when I'd say they are less of a risk now based on them being debt free and unlikely to repeat the same mistakes again given what most have had to go and endure during the 5 years in a IVA.
You could also approach a broker as previously suggested, but expect to pay a fair deal in broker charges (some would agree it's worth paying) and still end up potentially paying more than someone else who is able to answer NO to the question "Have you ever been bankrupt or made arrangements with creditors"
Hope some of this is useful.
We're willing to wipe the slate clean, give you a fresh start. All that we're asking in return is your cooperation.