Electrical goblins

Having a little trouble with (possibly) alarm system. When I lock it with button all seems ok, indicators flash to confirm. Unlocking ok, immobiliser works as it should ie if not started straight away it activates but can be disabled as it should. BUT, once locked after a varied time ( 5 mins to 2 days) the o/s rear indicator comes on solid inc side repeater but not the front one, and indicator dash light on as well, and both stay on after unlocking unless I either lock & unlock or press the hazard switch on and off. It is a disco 1 first reg'd October 97 300tdi ES. Now there seems to be a lot of faults discussed on here regarding the "spider" but this seems to be all related to the immobiliser side of things. I've also read that a 97 may not have this fitted, if so does it also control the alarm system? As there is an alarm unit fitted to o/s inner wing near the engine bay fuse box, this appears to be a factory item ( correct me if wrong ) as the wiring from the multiplug is in the main loom with original wrapping on it. I have also disconnected this and it has no effect either to the problem or starting of vehicle. I tried the "test procedure" as in the workshop manual but nothing, not a chirp or peep. All other electrics work faultless, hasn't been an issue until now as been doing all the welding and bits and bobs so been disconnecting battery overnight, but just passed mot today and will be on the road once taxed at end of month, so that will no longer be a practical solution. Sorry if it's a bit long winded, but wanted to give as much detail as poss. Any auto sparks, please help.

What u are looking at on the o/s inner wing is the battery backed-up alarm sounder, not the security systems control unit. Have u checked that the indicator relay is ok?
Also you won't have a "spider" if your engine has EDC.

Yeah, all indicators and hazard work perfect, it's just when it's locked, sometimes it acts up after five minutes other times it will be lock and left 2 or 3 days before lights come on

UPDATE,
Ok, so today I got hold of a good used alarm control unit with key fob. It is the green unit under the dash in the passenger footwell and all is well. The alarm an immobiliser now perform exactly how they should, I also got the siren unit from engine bay and it also makes all the right noises as and when it should. Hopefully this will help people with similar problems on models that do not have the "spider" fitted.