We have 3 areas of torn roof felt. 2 of I am pretty sure caused by us (DH) over enthusiastically shoving something tall up into the loft!! 
. This could also be the cause of the third area too tbh - he is a hoarder!!
So anyway, my question is - can it be repaired fairly easily?
I am hoping it will not involve the roof being taken off. Please please tell me it can be repaired/replaced from the inside. I am wondering if they would replace a whole strip of roofing felt or patch repair it.? One area is right at the apex of roof so in fact 2 pieces of roof felt are hanging down from the top a little (torn). I can see the tiles through the hole.
It has been like this for a little while now and so far we havn't had any leaks up there however, the longer time goes by the more I worry and so really want repair it - or more than likely get someone in to repair it.
Before I start calling roofers I wanted to ask if anyone else has repaired torn roof felt and what it involved and any rough idea of cost - although I know this will differ vastly from roof to roof and area to area.
One thing I need to consider is that this very probably is not our forever home and it is likely we will move in 5 or so years, so I would want a decent job done.