Unsure about safety of lighting circuit

The lights in the upstairs of my house (loft conversion) seem rather dodgy.

The loft was converted recently (before i lived in the house) The lights occasionally flicker, others dont notice but im aware of it and it seems to flicker only once evry 15 minutes or so. Its mainly spotlights in use and they dont seem to last as long as id expect. (downstairs circuit not effected)

After checking other posts i read that this can be caused by loose neutrals, ive checked the CU and tracked cables where possible to ensure everything seems securely connected inside joint boxes etc...

At this point i was wondering if maybe a cable was under rated but there is a 1.0mm cable that goes from the CU to a joint box, splits 3 ways to both bedrooms seperately and to the hall. at these points it is connected once again via a joint box to the lights and switches in each area.. if i have described that decently does it sound normal? as you can see ive done a lot of investigating and dont seem to be finding a problem so its annoyin me...

The lighting circuit contains 9 lights and from my calculations shouldnt take anymore than 2 amps although my calculations dont count for much.....

can anyone help me, sorry if that isnt clear enough.

Do any of the other lights in the house flicker? It can be caused by loose lives and neutrals, equally. With this being the longest (possibly) circuit in the house, there will be slightly more volt drop, but not much as the loading isn't significant.

Neighbours turning on high-powered appliances like showers and arc welders and particle accellerators will cause your lights to flicker somewhat, as the volts drop on the local distribution network.

Have you checked the connections in the switch and the light itself? Lots of junction boxes are ok on a lighting circuit. Ours has about 6-7 in the loft, because of the way it is wired.

is it a flicker ie off and then on or is it a dimming momentarily?
Sometimes a fridge or freezer cutting in and out will cause a momentary 'flicker' of the lights, particularly in older properties with older wiring systems.

it dims momentarily and then works as normal, its just a milisecond it flickers for but im sure anyone who has experienced a similar problem will know how frustrating it is.

Looks like its gonna be a chase the cable game again to check all the connections.

anyway im new on here and im surprised at the rapid responses, thanks all.

forgot 2 add there, none of the other lights appear to flicker. this is common only to the upstairs lighting circuit..