a LITTLE advice please

hello, I chopped in my discover a few months ago but landrover fever has come back upon me in the form of a 2a and now the fun starts.
I've brought her as a non runner, the chassis has all been welded up and an ex mod diesel engine has been fitted in place of the old petrol one. It is a 1968 but has a series 3 dash which i assume was wired up for the petrol engine.
The wiring has all been cut / removed around the engine bay but can still be seen in 6 binch lengths so I assume they could be connected again by splicing a piece in. Could anyone advice on things I need to watch out for, if it will need a new loom or if I can just use additional wire. I have an experienced mechanic to help me but any specific advice from people who have done it would be tip top.
many thanks in advance

not done it a ex mod diesel b4. But i doubt a new wiring loom is needed. Just need to connect wires from the starter solenoid to the relevant parts.

I am assuming of course that the wiring loom has not been cut from the rest of the vehicle.

If the whole loom has been butchered then a replacement might be better, unless your skilled in auto electrics, if its just the engine bits that have been snipped then you can reconnect them no probs, you just need either a pushbutton or another ignition switch and relay for the heater plugs.
You say its a series 2 1968 with a series 3 dash, I'm not saying it is but are you sure its not a series 3 with a series 2 registration, seems to happen a lot.

buy a few reels of wire and start again from scratch, that way YOU know what's what with the electrics

hello and thank you for all the replies, really helpful as I was thinking i could have brought a disaster!
The wiring has all been cut, no idea why this included all of the lights etc but assume the loom is in place or at least the central bit of it. A push button start is mention would this be preferable to a traditional ignition? i like the idea and assume i'd just need some way of cutting the power to the button when it's parked in town etc.
As for the year I have no idea but the dash does 'look' standard but I haven't picked the truck up yet so hard to tell. I did have a series 2a that was H reg with a centre dash this one is a E or F but with a later dash can anyone tell me why this should be?
I'd also be interest to know your opinions on the time I should set aside for the job if two people are on it one skilled and the other (me) cutting wire and asking questions

You want your lights and things to be reliable so only do the job if your confident with it, replacing the 'ole lot would be quicker but would cost more, make your own mind up.
I wasnt suggesting pushbutton start, I was suggesting pushbutton pre heaters, I'm sure you know that diesels have electric heater plugs, if the car was a petrol then it wont have wiring for it, and the ignition switch on the diesle landy is diffo, theres an extra position for the heater plugs, so you can either use a proper ignition switch, or what I did with mine is fit a pushbutton and relay for the heaters, if you get a beefy pushbutton rated at 40amp then you wont need the relay.

oh yeah now I remember! sound infinitely sensible so I'll do it!