Tool for transfer box oil filler?

I tried to check the transfer box oil level on my recently bought disco 2 but the handbrake cable is even more in the way than on my defender. Well actually I assigned my 19 year old son to do this after he checked the front and rear diff oil levels while I was doing something on another car. For the defender I used a regular 1/2 racket but it isn't fitting in! Are there any tools available with thinner head that people use?

At work I have some flat steel with 1/2 square welded through it for tight jobs on belt tensioners, would also work for you, easy to make
Ive also used regular ratchet with a wobble extension, to get past the drum.

Iirc, I used a std ratchet with an extension fitted and pushed the handbrake cable out of the way. A bit of a PITA but possible.

Cheers

thank you