I am a director of a small limited company and want to fund a pension directly from my Ltd company.

Depending on the size of the company and how many people would need to be included in the pension really dictates what type of pension you need to set up, but the admin costs can be very expensive.
If you are simply looking to set up a pension for yourself then i would recommend you set up a SIPP with someone like Hargreaves Lansdown. You can choose what goes into a SIPP and how you want it invested. You can pay more in when times are good and stop payments when you need the money for other reasions, as they're much more flexible than a normal pension. http://www.hl.co.uk/pensions/sipp
I ran my own small Ltd company until very recently and that was the route i chose. Depending on your turnover and how you choose to pay yourself - I took all of my salary as divs twice a year to avoid tax and ni, and payed corp tax on the co profits as that was the lower overall tax take - and how much you need to take out of the business compared with how much you want to invest into your pension, then paying into a pension is a great way to minimise your overall tax bill.
But without knowing your personal detailsit is impossible to give you the best answer. As a Ltd company you will - i presume - have an accountant so that really is the best place to start. He will know your business inside out so will be able to give you the best advice.