Like most people you went to a sub prime lender to secure a mortgage due to previous poor credit. For mainstream lenders like the halifax borrowers on average stay with them for 13 years. With Sub Prime its 18 months.(posted 7706 days ago)The reason being is that people like yourself have to prove to the high street that you are worthy of lending to again and this takes about 18 months - 2years with sub prime. I cant guarantee anything but if you have been with Platform for 2 years without missing a payment then your chances of getting a mainstream mortgage are very high.
I would advise giving a broker or another intermediary a try to get a good deal and take the hassle out of things, but you may want to try approaching someone like the halifax yourself first to test the water.
They are still likely to reject you though if you have any unsatisfied CCJ's or other matters that are likely to affect your credit scoring.
If that does not work, stick with the sub prime market for a while longer but shop about for some better deals. Kensington are doing a fixed rate of 4.75% for a year. Mortgages plc are doing a fixed rate for 4.99% for a year.
The only caveat I can think of though is your redemption penalties. Most sub prime lenders charge about 6 months of your normal monthly payments if you redeem within 3 years.