Which mortgage should we aim to pay off first

Futuresavings

Hello
We are after some advice please. 

We have 2 mortgages  
1) £17,000 now on a tracker at 6.3%, with 8 1/2 years of the term remaining. Payments should be £209 we are about to start paying £500 a month. There is no early repayment charge.
2) 130,500 fixed at 2.79% for another 4 1/2 years.  This mortgage has 14 1/2 years of its term remaining. Payments should be £945; we are paying an extra £120 each month.  There is an early repayment charge of £6800, but we are very unlikely to be able to overpay each year the amount that would incur an overpayment charge (max overpayment is around £16k). 

Our aim is to try to overpay as much as possible (currently we are ensuring we have 3 months spend in savings following MSE advice). 
Though we are overpaying each mortgage each month, we can't agree, if we have money left over each month, whether we should be concentrating on clearing one first and if so which one. 

Ideally we would like to reduce the mortgage as much as possible and if we are careful we will have £700 per month left over. 
Should we overpay the larger interest, but smaller mortgage?
Or the larger mortgage with smaller interest (for next 4 1/2 years anyway) after which we will go onto a potentially higher interest rate? 

Any advice will be very much appreciated.

saajan_12

Without a doubt the 17k 6.3% interest one. 

AFTER you pay that one in full, if you have money left over, then the options are
a) put it in a high interest account ready to pay off a chunk when the fix finishes and then remortgage at a new fix
b) overpay the 130k 2.79% mortgage 

Which one depends on the max overpay without ERC, how much money you have towards overpayments, tax band, other savings etc. 

Orangetoes

Yea definitely the 6.3% interest one first. 

South_coast

The larger, cheaper mortgage is actually costing you a whole lot more though. The £130k mortgage is costing you £303 a month in interest, but the £17k is only costing £89. Someone will no doubt tell me I've got it all wrong, but if it were me I'd be paying as much as I could off the larger mortgage and then if I hit the fee-free limit I'd divert the money to the smaller one

beanielou

The smaller one as it has the highest interest.

Futuresavings

Thanks all. I have been steering more to the smaller mortgage with bigger interest, but my OH is thinking along the lines that the larger mortgage generates more interest each month. 
Going to concentrate clearing the smaller one (that's my intention at least), then we can concentrate on the the bigger one (and the problem of which one to overpay will be resolved). 
Appreciate everyone's advice on this, thank you.