Osborne Heli Tours were very accommodating with the wheelchair, and they had no issue at all welcoming me onboard one of their helicopter flights. The guys that worked there were all very friendly and helpful.
The location is step free including the entry to the office to check-in for the tour, however the grounds to the helicopter from the office is made of small pebbles which is a little tricky to navigate in a wheelchair. I managed the pebbles ok in my electric wheelchair, but manual wheelchairs might need a helping hand.
Mum picked me up and transferred me to the helicopter without too much trouble before they started up the helicopter. Nicky sat in the front to get some awesome Go Pro footage, while mum and I sat at the back. Once we were seated, the guy on the ground then pushed my wheelchair out of the way and stored it until my return.