Hi jedichi and welcome to the forum
If you can afford £300 per month over the next five years, you would be close to paying off your creditors and therefore an IVA may not really be suitable for you - especially as you only have three creditors.
If you are insolvent your credit rating will be affected similarly whether you apply for bankruptcy or enter into either an IVA or a Debt Management Programme, given that it will appear on your record for six years.
I suggest that you explore debt management options as well as the IVA, as this may provide you with a more flexible route to debt repayment.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
To have me propose an IVA for you, please visit:
http://www.melaniegiles.com/ivaEnquiry.asp
See customer feedback at:
http://www.iva.com/iva_companies/IVA_Advice_Bureau.asp