If your buying a second hand home (not new) you will only be able to get a 60% mortgage, More on a new one. You also need to raise around 10% of the house cost to cover fees too.

You could try to re mortgage your UK home / raise funds here to cover it.

Or you could try the Halifax who do mortgages for forign house purchases.

another way is to get the bank to over value it, 100% morgage given friends of ours have done here

i think it depends if you mean not paying a lot of money up front for an off plan or if you simply require a high percentage mortgage. On a new build a 10% deposit will suffice if you are able to complete within 3 months, although this doesn't necessarily mean you would be able to get a mortgage for the 90% balance