charge problems

hi guys, had a look round and although theres some good advice nothing seems to match exactly my situation

having trouble when starting my 1992 200tdi disco, turns over very slow, like the battery is dead, but usually will do this 3-5 times then start. sometimes wont and needs a boost from another car
when i eventually get it going i have no revs on the dial and if i rev a belt squeal can be heard, i assume its the alternator 'coz the revs come back up when the noise stops. usualy 30secs to a min.
the noise also comes back sometimes when i steer and always when i fully lock the wheels either way. had a new belt about a month ago and tried re-tightening it twice.

i can normally restart her straight away within 2 hrs of initial start and a run, any longer and the 3-5 slow turn situation rises. but, i checked the battery the other night and it read 12.something and 14.something when idling, which would suggest alternator working? and this was around 4 hrs after turning off (maybe too soon for accurate reading?)
after a day offroading yesterday though, i had no revs and no noise for a while, then came the noise after 30 secs, n the revs when noise had gone

i have borrowed an alternator off a friend so i can strip mine to check

if anyone can understand what i wrote, i'd be happy of some pointers
mark

get a new battery,alternator sounds like its working

battery is varta e7 (70ah, 510a) only been on since sept. had same type on my old disco for a year with no probs. also have split charge system and the secondary doesnt charge properly?

The rev counter comes from a thin lead on the back of the alternator, so 1st check that is sound and replace as appropriate, sounds to me like it is bare wire somewhere causing a short.

The starting could be down to bad earthing, so go round all your earth cables and clean, detach, copper slip on them and retighten.

new 700cca battery & belt and cleaned earth points & alternator. seems to have worked. but im curious as to why my alternator belt sounds like its slipping after 3/4 weeks use?

had very similar on my 200 turned out o/s front wiring harness was in a mess of decay. dint find it for ages untell i striped loom down. Any seemingly unrelated nigles with electrics ie cig lighter dash lights? break out asprin could be headace time