Mortgage advice for second home with partner

kenvil

hello and thanks for anyone that offers useful advice in advance.

This outlines my current dilemma

My partner and i have just sold one of our current houses for 125k, which leaves us with 1 more that has a mortgage for 73k (in my name, not a joint one) and is valued at 145k but am having difficulty selling it, as the offers are coming in at 130-5 and i begrude selling it at that.

We have bought a new house together for 275k, which one we have cleared some loans, leaves us with a new mortgage on that house for 180 k.

My question relates to what do you do when you have 2 mortgages. Can we get a second mortgage with a different lender ??

Your estate agents advisor suggested switching the mortgage we have already to interest only and getting renters in, which we can expect 600 pcm from, but im not sure nationwide will allow me to do, but he feels we should be able to do. As i do not have 150k equity in the house as it states you must. Can anyone confirm we can do that ??

One more question, what should i be expected to pay on the 180k mortgage, when the estate agent was showing us, the smallest figure was 950 pm and when i have done some research over the weekend, rbs, abbeys are about 750-800, why would the experts figure be so much higher, or am i likely to be missing something ??

thanks again

Ken