pull ups

Also try negatives. Jump up to the bar and lower yourself as slowly as possible. This builds strength. Or jump up to the bar and hold yourself up for as long as possible in place. This will also build you up. (You may not want to do this if all you have is an in the doorway bar, it may rock) If you have a stable bar, I would also buy the flat band. You can find them at Academy Sports cheaper than the p90x assist. They come in different assist varieties. But I would start with the jumping to the bar and build yourself up. You can also find a demo online on having a partner assist you with pull-ups. Basically you are at the bar and your partner holds your feet against their chest (your legs are bent behind you on their chest) and you push against their body with your feet as you push up.

Also try negatives. Jump up to the bar and lower yourself as slowly as possible. This builds strength. Or jump up to the bar and hold yourself up for as long as possible in place. This will also build you up. (You may not want to do this if all you have is an in the doorway bar, it may rock) If you have a stable bar, I would also buy the flat band. You can find them at Academy Sports cheaper than the p90x assist. They come in different assist varieties. But I would start with the jumping to the bar and build yourself up. You can also find a demo online on having a partner assist you with pull-ups. Basically you are at the bar and your partner holds your feet against their chest (your legs are bent behind you on their chest) and you push against their body with your feet as you push up.

This is what I did...reverse chin/pull ups...works like a charm.

Thanks!
The bar is in the loft hatch! So with a chair I reach it fine - but I can't high up enough to do a negative!
I think the band will be the way to go then! What poundage do folk normally start with? I can't even do one myself although having a helping hand from my other half I can get up a few reps!

You could (and this carries an "at your discretion" disclaimer) consider placing a stepladder under the loft hatch so you can hold onto the bar but also rest your heels on the rung of the stepladder so they are parallel to the floor below and pull-up like that. In this way you are lifting around two thirds of your bodyweight and your legs are not taking part in the work. Placing your feet on the step enables you to push slightly so you could start on your heels and then switch to toes as you start to reach failure, then step up on the ladder to reach the negative and slowly come back down, back up the ladder and down and so on.

Mind your head though!