Allotments 4 All

I can't remember if I've asked this here before but here goes:

I have a 2nd hand trailer and a 4x4 (the tank) with a tow ball on it.  The tank's too high off the ground for the trailer to couple with it, resulting in the back edge of the trailer is too close to the ground when unladen. Laden, it would become dangerous.

I understand that the trailer's tow hitch can be raised - or replaced with an extra-high version - but need to know what kind of place to contact, what to ask for, if it's a complicated job requiring strength or if a lass with good DIY skills can manage it.

I know these people are good for trailer parts but the website looks a bit of a maze not knowing what your part might be called, there probably is someone more helpful than me about this!!

http://www.indespension.co.uk/