Good on yer, Blister, I am sure you won't regret it. I bought the Oneida Super Dust Gorilla (stupid name) before Axminster's version became available, and I'm very pleased with it. Shame the importer went bust. You have a couple of refinements that would be good on the Oneida - the viewing window in the waste drum and the automatic filter basher.
Are you planning to plumb it in with permanent ducting? I would recommend it. You need to get the ducting design right, but there are plenty of resources available on the net and in books to help you do that. Mine is in spiral metal ducting which is quite cheap and the jointing is easy with a pop riveter and allows you to make small angular adjustments, unlike plastic drain pipe. It is also available in a wide range of diameters so you could start by throwing away that three way adapter on the inlet of the machine which would help efficiency. One thing I installed on the recommendation of another Oneida customer is a floor sweep duct. This almost makes sweeping the workshop a pleasure - no more clouds of dust, just open the floor duct, switch on and the air strong airflow ensure that the dust you create when sweeping is drawn into the machine along with the shavings.
What's Dagenham like these days? I grew up in its posh (!) neighbour, Rainham, many years ago.