I would be tempted to cut that off and weld a box section frame on underneath with a couple of gussets for added strength
Get this bought Ken, i've got a towbar bikerack and it fits perfect on one like this http://www.ebay.co.uk/itm/vw-t2-bay...arts_Vehicles_CarParts_SM&hash=item43c3f95b7e
the box section tow bar will be fine IMO Ken, provided you're not towing anything major, but the fact that the section with the tow ball is open channel means that it will definitely flex...the simplest way to reduce it would be to drill two holes up thru the base and then stick two bolts thru with a nylock on one end, and two additional nuts/washers inside the C section, to brace it.....if you've got a welder, two end caps would do....bikes are about 30lbs on average....that's neither here nor there weight wise....
the one i have is good for me but it is a tiny bit flexi i think im just being a bit fussy but works well apart from that ,it also has two holes on bottom all i was trying to do was get some idea how to stop the flex . i think your right that will do it thank you thats the sort of answer i was looking for
wor definitely worth a try before shelling out on stuff you don't have to....I'm thinking along the lines of M12 bolts