Channelled pipes for towel rail

[smallsteve1]

In the middle of a bathroom refurb and need to replace existing radiator with a towel rail, but I am uncertain on the best approach to take.

My first idea was to use the original (channelled) pipework along with (additional) chrome pipe and fittings, to compensate for the new position of the rad outlets - see pic 1. The problem I have hit though is that the existing pipe is brittle and needs to be replaced. :-/

Now my options seem to be as follows:

1. Reuse existing channel with new pipe + external chrome pipe, along with a straight valve
2. Cut new channel from floor to required position and then use corner valve
3. As per 1, but extend diagonally from existing end-point to new position, again, using corner valve - see pic 2, with ‘x’ being the point of exit

Issues (referencing numbered items above):

1. Not sure about going at the same breeze blocks a second time? Pipework might look a bit naff
2. Channelling a wall that has previously been channelled, close-by
3. Channelling of pipework that is not horizontal / vertical, frowned upon?

On a related matter, i was thinking of using a Speedfit coldform to achieve the 90° angle and then use a piece of 15mm pipe to act as a protection sleeve for the 10mm pipe - pic 3. Maybe go as deep as 25 mm and backfill with bonding coat?

TIA