fueling running issues

morning all ! I've got a first gen mille owned this bike for ten years without any real issues until now !!!!!
it all started with several relays falling over winter and a few wiring and switches issues which are all replaced and fixed
now I have a new issue ? the bike starts and purrs like a kitten but as soon as I put her in gear the bike dies and all the dash board dies and just the rev limit light stays on ? take her out of gear fuel pump primes and all lights come back on and I'm able to start her again,
put her back in gear and the same happens ? so thinking it could possibly bit the tilt switch as this is designed to cut the fuel, I've also just replaced this and still have the same problem very confused now ! what I've just discovered is that if I unbolt the front of the tank and tilt fully up in gear all the lights come back on dash works and pump primes and will run but a bit rough.
please help as its driving me mad

Thanks for the reply. Side stand is linked out and the dash goes out when in gear only ? it makes no difference if its running or not, its the same result the bike dies, the only thing lit or working is the rev limit light on the dash ! take it out of gear and the bike will start and run normal. Ive found that when I put in gear the neutral light is still on then bike dies . I'm not the best at electrical and I haven't a wiring diagram so its been a slow process, I've been told the clutch safety switch is also the stand switch is this true ? And yes the tilt switch is right way up ( pissed off I bought a new one and still not working) so not sure what's going on with the tank ? Ive also plugged my spare fuel pump in and same result confused! any advice is very welcome and appreciated