Don’t go for water-cooling in your workstation because:
There are more points of failure: Pump-failure, leakage/evaporation.
They tend to be noisier.
Unless your hobby is overlocking, they are unnecessary.
You want simplicity and reliability over everything else.
There, you just saved ~£100 by not going for water-cooling. (The cooler and the case to accommodate the radiator).
The socket 2011-3 is ideal for workstations but has since been replaced by the 2066 socket. The benefits of both of these sockets are: They can take 128GB of RAM instead of 64GB, have four 16XPCI-e slots which is a great benefit if you have the money for 4 top-of-the-line graphics-cards for GPU rendering, they can also accommodate processors with many more cores. However, there is a trade-off between core-count and core-speed. Only in tasks like rendering do core-numbers above 4 really matter. For everything else you want fewer and faster cores.
With a small budget, I don’t know if you’d benefit from either the 2011-3 or the 2066 sockets as high-core-count processors are still really expensive. Whilst either 2011-3 or 2066 would offer a greater upgrade-path in the future, you never invest in computer-parts! You buy only what you need at the time. So there might be a case for a socket other than these two, but 2011-3 should be quite cheap now that its successor is out, so I don’t know.