Moving up the property ladder

Hello,

Please forgive me if I'm being a bit stupid, some things i've ready on the house buying forum have set me wondering and I thought this may be the best place to ask my questions!

My fiance and I are currently living in our first bought property. In 2010 we took out a mortgage on our 1 bedroom property. We paid £115,000 for the house and the mortgage was at 95% LTV. We were fixed for the first two years, and are now on a variable and overpaying the mortgage by about £150 a month (basically we've kept up the original payment)

My question is this, as we will need to move up the ladder when we have children, will we be in the same situation with the deposit as we were initially? i.e if we buy a house worth £200,00 and need a 10% deposit we will need £20,000 cash either from what we've saved or equity (doubt there will be much!) from the house to give to the mortgage providers?

It might seem very obvious but I just thought i'd ask as something set me wondering that I read in another thread!

Thank you in advance :)

Rachael