On 20/07/2010 15:09, Lordspudz wrote:

Can someone please enlighten me on a few points?

1 Which is best - horticultural glass, toughened glass or polycarbonate
panels?

Piece of string question.
Horticultural glass tends to break into jagged shards (VVVV dangerous
(IMHOYMMV)) bit like window panes in horror movies, NEVER have HG above
you. Polycarbanate tends to get blown about in a wind. Toughened glass
has a tendency to shatter rather than just crack so can not have the odd
crack taped over .
If the expense is no object I would go Polycarbonate (with good
glasing bars) Toughened glass then Horticultural glass

2 Is it necessary to have a base fitted to the bottom of the 'house'?

Not necessary depending on make/model of greenhouse.

3 Can automatically opening vents be fitted to replace manual opening
ones without too much alteration?

We fitted an automatic vent opener in place of a manual in a couple of
minutes and have had no problems since.

4 Is it good practice to line the house with insulation such as bubble
wrap?

In the winter, yes (along with screening for very sunny days)