The first port of call may be your existing lender who might be prepared to help. Given that your IVA has been discharged more than two years it is certainly worth considering speaking to them.
If this is not an option you could try a broker but be careful of large fees and interest charges. It may be best to rent until your credit file clears up and you can then sell and buy another property with a high street mortgage.
You non longer are sub prime as you are out of the IVA over 2 years. It may be worth writing directly to the lender and an underwriter could review the case rather than dealing with an advisor in a call centre.
Andrew Graveson who posts as an expert on the forum has a great new contact for mortgages for people who have successfully completed IVAs, and am sure would be happy to put you in touch. Definately worth a try.