Best 70% LTV Mortgages. Please Help

Hello Everyone

I am hoping to buy an house for around £282,000 and have a deposit of £85,000 meaning I have 70%

I have been looking for deals on best, the three best deals that stand out are Northern Rock (Virgin Money), HSBC and Santander. I am looking for 5 year fixed deals only. Below are them

Northern Rock: 5 Yr Rate 3.05%, SVR 4.79%, Product Fee £995

HSBC: 5 Yr Rate 3.19%, SVR 3.94%, Product Fee £599

Santander: 5 Yr Rate 2.99%, SVR 4.74%, Product Fee £995 (£250 CashBack also)

I am confused as the above are very good deals, however HSBC allow the 20% overpayments every month whereas Northern Rock and Santander only allow the 10% every year of overpayments.

What do you guys recommend. Your advice is invaluable and as I am a first time buyer I dont know much about this.
I already have my mortgage in principle by Northern Rock, but not the other two.

Thanks