Congratulations Ben!!!
A lovely little engine, and unlike your initially intended purchase, i dare to promise that this one will actually run when fired.
Looking forward to see what choice you make, when it comes to firing this.
PS.
If it was me, i´d just fire it as is, and make fists with my toes while the paint crumbles.
It can always be repainted if so wished for...and a new firebox is listed for approx. 13 bucks on Jensen´s online parts list...just saying 
Thanks for the tip of Spare Jensen "bricks" boiler house available at low price Jan.
That is a Part that Wilesco will not sell you....it seems if you have damaged your Wilesco bricks, you have had "to much fun" and your "penalty" is you must buy a new engine to get more bricks
