Is this a good mortgage deal?

I am in the process of remortgaging my house in the UK. Yesterday I got a quote from the broker on a remortgage of �179,000. The quote I got was �140 more expensive than my monthly budget allows but on paper it seems a good enough deal. It is a 25 year mortgage which is fixed at 5.69% for 5 years meaning a monthly payment �850.00. At the end of the period, the mortgage will revert back to the SVR and the monthly payment will be�523.52. At the moment I am on a variable tracker mortgage (which was previously a fixed 3 year deal at �1048.pp per month) for which I pay �450.00 and it is 2% above the Bank of England rate. So, with that in mind is it a good deal, and should I take up this offer?