I have coded a fully functioning shopping cart, everything works great! the thing is we haven't gone down the route of assigning weights to each product (around 900) is there a way i can assign a delivery price without using weights at all?
Shipping is always the hardest thing to work out. Sometimes the answer is to work backwards - see what the costs are and then backtrack the calculation. I've often opened up a spreadsheet and created some scenarios to play with to try and find a workable method.
One approach might be to have a sliding scale per item, ie
...and so on. Don't forget there always comes a point where a high shipping fee will actually put people off buying, so having a ceiling shipping level is worth considering - also with larger orders you can absorb some shipping cost with the product price, albeit at the expense of profit - but that can make the difference between sale and no sale. Would you rather have a sale at a lower profit margin or no sale at all?
Another option would be to offer "free" shipping for UK orders, but include a markup in the product price to cover the bulk of the shipping costs.
Of course weight based shipping usually solves most of the headaches, because you can calculate the exact fee per order!