i have just stripped and reconned my td5 starter, would anyone know how to bench test it to make sure it works properly

You should be able to test it spins by putting on positive and negative then applying positive onto the solenoid which will cause it to spin up. Make sure it is clamped in a vice though!

As already mentioned make sure its well clamped. Dont try to hold it or you'll break your wrist.

most safe way is using jump leads on the starter, so that when you touch the battery it spins (fit to starter first, ground connected, touch positive jump lead to battery to start). Put it on the ground, have 3ft around it nothing you'd not like to be smashed. If it spins, it should rotate fast and should sound "round", maybe with a slight whistle. As mentioned, dont try to hold it or fix it without a proper testbench. The forces are very high.