Great thanks for all the advice folks.

remedying it on the cheap is definitely my objective.

If the only danger will be caused by water coming through, I will
seal the hole more permanently to keep water from coming through - In proper blue peter style, I'm thinking of a sheet of sticky backed plastic, or maybe just silicone sealing the aluminum sheet I have there into place.

I know it wont last for ever, but it should keep water from doing any more damage.

this is a great forum - I'm sure I'll be back with more silly questions - thanks again