Would the property actually sell if it was put on the market bubbleandsqueaks? If you put it on low to sell would you have enough to have any cash left over? The credit rating issue with renting can be overcome if you have a relative who could be a guarantor for you on your rental.
In answer to your question....If you rates rise and you can't afford the mortgage, you stop paying, you save up a deposit, six months rent and costs. It will take you lender some time to repossess you, up to a year (once you know that there is no hope that you can ever afford to stay in your property there is no point in paying your lender any more money, they will take your last penny and still repossess you.) Your local council will have a duty to help house you, because you will have a deposit you will have more options and will not be homeless. Crazy thing is, if this happens, you can role your mortgage and debt up, become bankrupt and be discharged within a year?.that is extreme but so is living in 'hell'.
There are options...there is more to living that having a mortgage on a house that is making you miserable now, just in case you last it out to provide some sort of retirement. Also, if you are renting and money is tight each month you may be eligible for housing benefit top up?
I'd definitely look into selling though?even if you sell at a swift price to a pro landlord. Have you looked at the renal market in your area and seen any nice places you might fancy living? Your only 30, you could sell, recover financially and still hit retirement having bought somewhere. You only get one go at life IMO...there is more to it than money and finances