Replacing the Seal on a Lewmar Hatch

[nigel1]

In the process of replacing seals on two lewmar hatches. Already discovered the overly complicated hinge arrnagement, but eventually had the hatch removed and then came a bit stuck when trying to seperate the two halfs of the hatch frame. Out of the 8 set screws, one was seized in and the head of the screw stripped. Not a big issue as only 4 of the screws need to be removed.
On refitting I need to use something to isolate the SS screws from the aluminium frame, but dont want to end up having to buy a gallon of something really expensive.
Can anyone suggest a suitable and reasonably priced product, which is hopefully available in the UK

[Soiree]

Tef-Gel
That is what it is made for, works.

[nigel1]

OK, got the tef-gel.
Any tips for fitting the new seal. The htach is the type with the split aluminium frame, and the seal is fitted around the acrylic before fitting the fram back over the acrylic and seal. I would guess plenty of silicone grease on the seal before attempting to slide the frame back over.
Any advise would be appreciated.