Depends on a lot of factors but we have just bought a house on a 95% mortgage last year and no issues with my £480 direct debt for the season tickets coming out. Plus the Mrs missed a payment on her card about 10 months before and that didn't matter. We were both on good wages too though and borrowing about half of what we could have borrowed.
We went with a mortgage broker too. Only cost us £200 but she did nearly everything for us plus you get access to different deals. They offer some great advice if you're first time buyers. Thought it was well worth the money
Also different credit agencies have different ways of doing your scores. I always had a shit one with the free ones, but signed up to the free trials of Expedia and equifax and had either excellent or just below scores.
Just look into it. Martin Lewis has a good section on his website too with lots of advice
Buying is the best thing I have ever done and should have done it years ago without wasting our money renting! Even though our mortgage is 95% we are paying less per month than what we used to when renting.