I am in similar earnings situation to you but all on my earnings (wife none). I am currently remortgaging (onto a split repayment & Interest only - 50/50 - for 332K on a 500K property) and looking at fixed deals too.
Best I have seen is West Brom BS with a 10 year 5.29% fixed, with fees of 999 + valuation and legals, which I reckon maybe worth a punt. Catch is you have to take the West Brom Buildings insurance (via NU) which is a bit steep compared to for example Tesco (brilliant for B&C insurance). West Brom loan max for the 5.29 deal is 250K, beyond this fees jump to 1% of loan value - however even for a bigger mortgage, the fees over 10 years aren't bad in my opinion. I have never fixed for more than 3 years before, but this I think is excellent deal still
If you dont like the fee structure, they also do a 5.39 fixed over 10 with free val & legals but still 999 or 1% set up fee - but NO compulsory buildings insurance (hooray). Even if the BOE drop the interest rate 0.5%, you would still be virtually on base rate with the 5.29 deal..
Theres plenty of deals in the 5.49 - 5.79 range with reasonable fees (2, 3 or 5 year fixed), personally I wouldnt fix on anything more than 5.59%, I think rates will drop and little and stabilise around the 5% mark over the next few years - but hey, none of us has a crystal ball !
Any other comments on this welcome, before I decide :-)
Chris