Aston Martin has raised £135m through a debt placing as it looks to shore up the balance sheet ahead of a production ramp-up later this year. The marque said it had raised around $90m (£70.7m) by issuing 10 percent senior secured notes and a further £65m through 10.4 percent senior secured notes, due to mature in 2029. Net proceeds from the offering are expected to be used by Aston Martin to repay borrowings under its existing super senior revolving credit facility. The carmaker has struggled for years under a burgeoning debt…