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, iīd 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 Jensenīs 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
