Thatcher Rock is only 300m out from the small bay on the coast but the tide rushes through the channel and a swim out and back has to be carefully timed. It is however a strange thing that due to the shape of the coast the current runs in the Meadfoot to Hopes Nose direction for probably 10 hours of a 12 hour cycle. It is perhaps ironic then that the best swim is into the tide from Hopes Nose back to Meadfoot.
Leave your car in the free roadside parking at Meadfoot and follow Ilsham Marine Drive and the coast path to Hope's Nose. The access is over a small stile at almost the very crest of the slope. At the bottom of the first slope either fork to the right which, if you are not afraid of clambering down a near vertical path, will take you onto the beach beneath the headland. Taking the left path, the one the fishing people use, will bring you out at the tip of the headland with Flat Rock aka Lead Stone Rock 100m out to sea. (It is a viciously jagged rock in bare feet and best avoided, though it is as the name indicates, one of the few places in the world that lead has allegedly been found as the native metal.)
Swim around the outside of Thatcher Rock and you will find that it slopes gently down to sea level. However, there the much folded rocks have been cut into bays and overhangs quite unlike the side seen from the shore which rises pretty much vertically from the sea. The rock ends in a sharp tip cut by several narrow channels that can be swum through on the right tide with calm water, anything else and you will be flayed by the barnacles.
Just in case you are thinking this is not sufficiently wild, there is a photograph on-line taken in August 2018, a day after I had swum this route of a thresher shark jump clear of the water where you are now swimming. Apparently they are not a threat to swimmers. I am not reassured.
Your route back to Meadfoot depends now on how you are feeling and where you left your car. The short route (1Km) is to swim to the steps at the car park at the right hand end of the beach. The middle way is to the steps in the small bay below the sea wall and that is where most of the parking is. The long way is across the bay heading for the grand façade of the Osborn Apartments, the slipway and the café (1.4Km).
The short route (beach-Thatcher Rock-car park) is 1.75Km (1.1 miles). The long route (end of Hopes Nose-rock-slipway) is 2.5Km (1.6 miles) and you will most likely have been swimming all the while into the current.
This is a crowd-sourced map. Abilities vary, and conditions change. Always assess risks for yourself before getting in.