My Swiftflow boiler's gas pressure gauge reads zero?

How do I re-ignite the pilot on my Glow-worm Swiftflow 75/80 ?

I returned from a week's holiday and turned the gas and water supplies back on, but the gas pressure gauge on my boiler reads 0 bar. (The instructions say not to ignite the pilot if pressure is below 0.7 bar). I don't recall that it had a positive reading before I turned the gas off, perhaps the gauge is faulty (?)

The other problem is, some time back, it stopped providing hot water form the taps if I turned the taps on ; I had to turn the boiler's Central Heating switch on to be able to draw hot water.

Can anyone help. please ?