Peugeot 306 - 306 rotates but wont start - gaz_r98aag

hi there i have a 1998 306 with a 1.4 petrol engine, guess i will go with the long story then it is easy to determine what is wrong with the car. i had it stood in the garden for about a year then decided to send it for an MOt it fired up first time and off to the garage it went they changed some suspension parts and a washer motor for MOT then i took it home and this is where the problems started.

everytime i went to start the car it struggled to start and when it did start would stall straight away until it was warm however everytime i approached a junction it would stall. i called the RAC out and they couldnt find the problem but suggested i change the relay behind the ECU, which i did but the problem still persisted, i took it to the garage to be plugged into the machine and they said there were no faults and it was probably because it had been stood and needed to be run in again.

after runnin it around a while it was still them same, however this morning when i went to it it wouldnt start but kept cranking. i took the a HT lead off and pluuged a spark plug into it but there was no spark while cranking the engine.

can anyone help me please i was told it may be the cranksensor, is this right? or do i have a more expensive problem!!!

many thanks

gareth