Advice on filter/pump for Koi pond for a complete beginner?

Hi there,

I am new to the pond world (complete begineer so please excude my ignorance)
as I recently moved and inherited a 11ft * 11ft * 2ft pond full with about a
dozen or so Koi carp, largest fish about 16 inches in length. The pump has
given up and the filter seemed permanently clogged up, even after cleaning
the internal (pads) every week. I have also noticed that the pond has alot
of "silt" in it even though the water is clean, it currently has a UV box
which now doesn't work as the pump is not working.

I would like to change the setup but don't have a huge amount of money to do
this, so I'd really appreciate some advice...So my questions are as follows
(apologies I have a number of queries!)

1. From what I have read the pond is too shallow (is it?) and needs to be at
least 4 ft in depth for Koi? If this is the case then I presumably would
have to remove the fish to a temporary setup (holding tank? any ideas on how
this is done?) dig the pond out deeper and replace with a new liner? Could I
use my existing pond for this season as is and make the changes regarding
pond depth when finances allow?

2. Should I get the pond cleared of the silt? How would I do this - using a
pond vac? Can you hire a pond vac?

3. What would be a good/inexpensive pump & filter combination? I have looked
on the web and it's a bit of a minefield of information, some people seem to
advise on a using a Vortex chamber setup or is this only for professionals?
What filter/pump would work with my existing setup as well as allowing for
the increase in pond depth at a later date?

4. I found a setup that looked interesting after doing some calcs on my pond
size, this was using the Hozelock Ecoclear 18000 with a Titan 12000 pump -
is this a good setup? This also looks good as I don't need a gravity feed
filter so can site this setup away from the pond, but the filters (2 of
them) do look a little small compared to my existing big filter box?

5. Could I also use my existing filter box (3 stage) with the new Hozelock
Ecoclear 18000 with a Titan 12000 pump system in line for extra filtering?

6. Any recommendations on suppliers? I found Grovelands Online
(www.grovelands.com) and their prices look great. I am based in
Hampshire.......

Any help would be very much appreciated as I am very keen to ensure my pond
setup is correct and enjoy the new experience of being a pond owner.

kind regards,
Richard