Existing lender vs New for refinance

[ayns]

Reading all this stuff about some properties now starting to be pushing back at the valuation (mortgage)  stage due to asking price vs actual value and some banks getting nervous about over valuing. 

I will have a house refurb completing mid November and want to get it re-financed as quick as possible ahead of any potential cooling off of the market next year. Some questions;

1)Am i being savvy by doing this now during this mini boom, guess no one knows what’s going to happen next year and my thinking is negative equity would be short term in my overall long term plan..obviously it would happy to be a mega drop in value to get to that. so trying to get the highest valuation possible is my idea to fund another purchase next year. 

2)are new lenders more will to give you a more favourable valuation than your existing? When I looked into remortgaging with my current lender they would only give me up to what worked out to be 67%ltv, hoping for 75%.