Existing Deal Ending Soon - New Deal or ?

Guys,

I currently have a mortgage deal with the Halifax fixed at 5.69% which is costing me £700 per month.

House value is currently £155k and I have 112k remaining on the mortgage.

I intend on putting 8-12k into the mortgage to bring the LTV rate to 65%.

I have excellent credit rating and the £700 is more than affordable at the moment (however I would like this reduced as much as possible)

I have been looking at Tesco (2yr fixed 2.79% £195 product fee) which should bring my monthly payments to below £465)

Is this the most sensible thing to do? How can I work out what my monthly repayments will be if I move onto the variable rate?

FYI - Mortgage is not due till June but would like to get a head start on it.

FYI - This is a single mortgage application, not joint
FYI - This is in Scotland

Thanks