Battery went flat and alarm kept going off so somebody removed something either under bonnet or wheel arch but cannot remember where to disconnect sirens. I have 2 keys, not fob type, and only one appears to work to switch off thatcham alarm immobilizer. Every 3rd attempt at opening doors the engine turns but alarm immobilizer stops it from working. I have to keep unlocking and relocking drivers door and wait and try again until it starts. Failing that I disconnect one lead and try again, then the other. Sometimes both and leave it sitting for some time. Then it starts or it doesn't. I go back to relocking doors to unlocking and keep repeating process until it starts. I find if I do a long drive and stick to one key it resolves the problem. Any ideas anyone please? Thanks in advance.