Also are there any online guide's available on the internet on how to
convert a loft etc, just for some guidance.

The loft conversion will be subject to building control (and in some cases
planning permission). The building control officer will need to have
structural details of how you propose to strengthen the floor. You will
probably also need structural alterations to the roof to remove struts which
will need careful design and calculation. There are a number of other things
that will need to be sorted too. Here's a list off the top of my head,
there's probably more.

1. Mains powered linked smoke detectors on every floor.
2. Protected main stairway to the outside (there are several options).
3. Escape window reachable by ladder low down so a children could be carried
through.
4. High levels of insulation to the rafters with either 5cm ventilation
behind the insulation, or breathable membrane (which requires reroofing, but
gives more headroom). This will typically require around 40mm from the
rafter, although this is variable.
5. Joists strengthening. This will typically raise the floor by around
100mm.
6. Approved staircase.
7. Firedoor at top or bottom of stairs.
8. Roof redesign to remove struts or insert Velux windows.

Christian.