European architects and designers are struggling to source wood for their projects as Russia's invasion of Ukraine has brought imports from the region to a standstill, threatening stocks and driving up prices across the continent.  Studios are reporting that costs for solid oak and birch plywood have doubled in the last few months, while others have seen the price of structural timber go up by around 20 per cent.  "Everyone is really worried about their supply chains," said Sean Sutcliffe, co-founder of British furniture maker Benchmark. "We have projects where it would now cost ...