Yes a Bayliner Capri is definitely over the 750kgs with engine and the trailer, plus the trailer has a 1600kgs gross weight plate, so should be braked to tow. Indeed, you must also tow it with a vehicle which has a towing capacity of 1600kgs, preferably above.
Those look like either Knott or Alko independant hubs, not an axle. You see there are two types, one is a torsion bar suspension which is a complete axle unit and the other type are single independant suspension units.
I suspect the trailer company you went to suggested suspension units because they are sometimes cheaper than buying all the bits and having them fitted.
Whether you change the suspension or buy another trailer depends upon your budget. You can sometimes pick up a second hand trailer for the Bayliner size for about £500, that'll sometimes be cheaper than new units plus cables, adjusters, etc. and maybe new wheels and tyres as sometimes the old ones wont fit new hubs. Having said that, a lot depends upon the sizes of the units. Older smaller brake units are actually more expensive than newer types and so depending upon how mechanically minded you are, you may be able to pick up brakes, cables and bits for not a lot. If you can find the sizes and the type then search through Trailertek, see below.
TrailertekIf you have somewhere to put the boat it'll give you time to research options, it might pay you to ring around recovery companies to see if they could transport it on the back of a truck for you for a fee. It's very risky and illegal to tow a boat which should have brakes which don't work and then it depends upon the type of vehicle you are towing with.