There are very few mid-airs between gliders and light aircraft other than glider / tug incidents - from elsewhere:
23 Jul 94 - Cessna 152 vs Glider mid air - minor injury to glider pilot
14 Jun 09 - Grob Tutor vs Glider mid air - both in the Grob died, glider pilot parachuted safely
6 May 12 - Mainair Blade vs Glider mid air (on landing) - microlight pilot seriously injured.
4 Dec 16 - Cessna vs Glider mid air - glider pilot died
4 in 24 years. There have been far more CFIT etc. in that time.