You would probably be better off taking your current engine to some one.... expect roughly £200 in parts (standard) so long as you don't need new pistons..... which unfortunately by the sound of it you will (no compression) but this may not be due to bore damage (could be head). And probably another 2-500 for machining and labour I have always built my own engines so im not sure how much companies charge. If you need new pistons these will be roughly 3-350 for standard mahle items.

Good luck

Rob,