By Chris Dorrell With debt at its highest level since the 1960s and growth sluggish, the next government will face some very difficult choices. The Institute for Fiscal Studies (IFS) suggests that the next government will inherit the worst set of fiscal challenges since the 1950s. Predictably both parties are reluctant to suggest they will raise taxes, but in recent weeks both have found a conveniently painless source of revenue: clamping down on tax avoidance. The Conservatives claim they can raise £6bn through tackling tax avoidance while Labour think they can find an extra £5bn. Sunak has a…