Having viewed your drawing i would suggest that you either;
Make the plate and tubes as a one piece moulding laying pieces of fabric into the corner such that it forms part of both the plate and the tube.
Make the tubes first, position them and layup the plate around them, again ensure some of the fabric goes up the tube. Obviously this method still requires that the cured parts are prepared for bonding correctly.
Araldite 2014 is good to 120 deg C and bonds well to composites.
As for surface preparation of cured composite parts, the general method is to abrade the surface (180 grit wet & dry) untill the surface gloss is completely gone, solvent rinse the dust away with acetone, MEK or similar fast evaporating solvent, then bond quickly.
If you are making parts and know you are going to be bonding them, put peel ply in the areas to be bonded so that when you have finished trimming the parts the peel ply can be torn off leaving the uniform matt surface ideal for bonding.
A bonded joint is only as strong as the weakest layer, if you want a strong bond, DO NOT wet some peel ply onto an un-prepared surface as suggested by AEROINVENT, if you prepare the surface properly (abrade and rinse) there is no need for a peel ply type surface, if you dont, the resin left behind when the wetted on peel ply is removed will not be properly bonded to the layer beneath and will eventualy come away.
Hope this helps
If a job is worth doing - Do it right.
There is never enough time or money to do the job properly - But there is always enough money to put the job right.