Thanks for all the help so far guys...this is a huge voyage of discovery for me and have learnt loads.....My plan of action ,to avoid throwing sh*t loads of £ at my engine is to rebuild it with the new head and get running...If it then sounds sweet I was going to do a compression check as the injectors are freed off now. That will tell me most of what I want to know...If the compression is good/ok then clean the injectors...thoughts and thanks Nik

test the injectors why they are out

While they are out clean them first then get them tested, at 160k could be weak springs causing them to leak, 160k is about the life expectancy of injectors, bear in mind that piston looks pretty compromised ( personally I wouldn't be fitting a new head on top of it) so you could well end up with far more serious problems, costing even shitloads morer than plain sh*t loads , even if it sounds sweet and you have good compression .